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1

Enhanced adsorption of acidic gases (CO2, NO2 and SO2) on light metal decorated graphene oxide.  

PubMed

The adsorption of several acidic gases (CO2, NO2 and SO2) on light metal (Li, Al) decorated graphene oxide (GO) is theoretically studied, based on the first-principles calculations. Configuration relaxation, binding energy and charge transfer are carried out to discuss the acidic gas adsorption ability of light metal decorated GO. It is found out that Li, Al could be anchored stably by hydroxyl and epoxy groups on GO, and then a strong adsorption of CO2, NO2 and SO2 will occur above these light metals. In contrast to Ti, Li decorated GO exhibits a comparable adsorption ability of acidic gases, but a much smaller interaction with O2 about 2.85-3.98 eV lower in binding energy; and Al decorated GO displays much higher binding energy of all acidic gases with an enhancement of about 0.59-2.29 eV. The results of enhanced acidic gas adsorption ability and a reduced interference by O2 imply that Li, Al decorated GO may be useful and promising for collection and filtration of exhaust gases. PMID:24777197

Chen, Chi; Xu, Kui; Ji, Xiao; Miao, Ling; Jiang, Jianjun

2014-05-14

2

Emission estimates of particulate matter (PM) and trace gases (SO 2 , NO and NO 2 ) from biomass fuels used in rural sector of Indo-Gangetic Plain, India  

NASA Astrophysics Data System (ADS)

In this paper, we present the experimentally determined emission factors and emission estimates of particulate matter (PM), SO 2, NO and NO 2 emitted from biomass fuels used as energy in rural area of Indo-Gangetic Plain (IGP), India. Biomass fuel samples were collected at district level from this region. The burning of the collected biomass fuels is performed by using the modified dilution sampler based on studies done by Venkataraman et al. (2005). In this study, the emission factor represents the total period of burning including pyrolysis, flaming and smoldering. The average emission factor of PM from dung cake, fuel-wood and crop residue over Delhi, Uttar Pradesh, Punjab, Haryana, Uttarakhand and Bihar are estimated as 16.26 ± 2.29 g kg -1, 4.34 ± 1.06 g kg -1 and 7.54 ± 4.17 g kg -1 respectively. Similarly, the average emission factor of SO 2, NO and NO 2 from dung cake, fuel-wood and crop residue over this region are also determined (SO 2: 0.28 ± 0.09 g kg -1, 0.26 ± 0.10 g kg -1 and 0.27 ± 0.11 g kg -1, NO: 0.27 ± 0.21 g kg -1, 0.41 ± 0.25 g kg -1 and 0.54 ± 0.50 g kg -1 and NO 2: 0.31 ± 0.23 g kg -1, 0.35 ± 0.28 g kg -1 and 0.54 ± 0.47 g kg -1 respectively). The emission of PM, SO 2, NO and NO 2 from biomass fuels used as energy in rural household over, IGP are also estimated in this paper. The result shows the regional emission inventory from Indian scenario with spatial variability.

Saud, T.; Mandal, T. K.; Gadi, Ranu; Singh, D. P.; Sharma, S. K.; Saxena, M.; Mukherjee, A.

2011-10-01

3

Simultaneous removal of SO2 and NO2 using a Mg-Al oxide slurry treatment.  

PubMed

SO2 and NO2 were simultaneously removed from a mixed gas using a Mg-Al oxide slurry treatment. Both adsorption to the oxide material itself and dissolution of the gases in the aqueous slurry contributed to the removal. A comparison was made between removal of the two gases separately and the simultaneous process. The removal of SO2 using both the simultaneous and individual process was similar; however, the removal of NO2 was lower for the simultaneous process. For the individual treatments, SO2 and NO2 were separately dissolved in the Mg-Al oxide slurry to produce SO3(2-), NO2(-), and NO3(-), which were subsequently removed by the Mg-Al oxide. However, when the simultaneous process was employed, the dissolved gases were seen to have a significant effect on each other. It was speculated that the production of NO2(-) was increased by the reduction of NO2 by SO3(2-). On increasing the quantity of the Mg-Al oxide, or on raising the temperature of the system, the removal of SO2 increased, with a concurrent decrease in NO2 removal. The increase in removal of SO3(2-) was speculated to hinder the conversion of NO2 to NO2(-), therefore decreasing the removal of the nitrogen species. The results demonstrate that the Mg-Al oxide slurry was highly effective for simultaneously removing NO2 and SO2 from a mixed gas. PMID:24125705

Kameda, Tomohito; Kodama, Aki; Yoshioka, Toshiaki

2013-11-01

4

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

5

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

6

Electron beam process for SO 2 removal from flue gases with high SO 2 content  

NASA Astrophysics Data System (ADS)

Flue gases with high SO 2 concentration are emitted from different industrial processes, e.g. combustion of coal with high sulfur content, copper smelting and sintering plant. The application of the electron beam process for SO 2 removal from such flue gases was investigated. A parametric study was carried out to determine the removal efficiency as a function of temperature and humidity of irradiated gases, dose and ammonia stoichiometry. At the dose 11.5 kGy 95% SO 2 removal efficiency was obtained when the temperature and humidity of irradiated flue gases and ammonia stoichiometry were properly adjusted. The synergistic effect of high SO 2 concentration on NO x removal was observed. The collected by-product was the mixture of (NH 4) 2 SO 4 and NH 4NO 3. The content of heavy metals in the by-product was many times lower than the values acceptable for commercial fertilizer.

Licki, J.; Chmielewski, A. G.; Zimek, Z.; Tymiñski, B.; Bu?ka, S.

2002-03-01

7

Differential absorption measurements of the NO2, SO2 atmospheric pollutants  

NASA Astrophysics Data System (ADS)

Differential absorption measurements made in laboratory on air samples containing NO2 and SO2 atmospheric pollutants are reported. This type of measurement is necessary to calibrate remote sensing equipment conceived to monitor NO2 and SO2 in open atmosphere using LIDAR techniques and to perform preliminary laboratory studies on differential absorption specific to NO2 and SO2 molecules. To monitor the mentioned pollutants, a nitrogen laser pumped tunable dye laser was used, the laser pulse having the following characteristics: energy per pulse 40 (mu) J, repetition rate 5 pps, pulse time width 10 ns. The dye wavelengths used to detect NO2 were (lambda) on equals 435.1 nm, (lambda) off equals 432.6 nm obtained from POPOP in DMSO and the spectral bandwidth was 0.7 nm; for SO2, (lambda) on equals 298 nm, (lambda) off equals 299.5 nm and the spectral bandwidth was 0.2 nm, the laser beam being obtained from R6G and further SHG by an ADP crystal. The concentration interval for NO2 detection was 18.4 ppm to 26.4 ppm, whereas the measurements for SO2 pollutant were performed at 6.4 ppm. The studied gases were home made and the samples pollutant concentration was measured by mass spectrometry.

Staicu, Angela; Pascu, Mihail L.; Cristu, Doina

1995-03-01

8

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

9

Micromachined thin film solid state electrochemical CO 2, NO 2 and SO 2 gas sensors  

Microsoft Academic Search

Among the many physical and chemical strategies used to make air pollution gas sensors for COx, NOx, SOx monitoring, those employing electrochemical detection means offer the highest selectivity, long lifetimes, low drift and low costs of manufacture. Targeting the three gases CO2, NO2 and SO2, new solid-electrolyte-based, selective potentiometric gas sensors were fabricated in both bulk and thin film versions.

J. F Currie; A Essalik; J-C Marusic

1999-01-01

10

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

11

Effect of buffer gases on the performance of SO2 trace measurement based on photoacoustic spectroscopy  

NASA Astrophysics Data System (ADS)

In this experimental work a laser photoacoustic spectrometer designed and fabricated. System sensitivity for detection of SO2 and NO2 was measured. Resonance frequency variation versus pressure increase of Nitrogen, Argon, Helium and Air buffer gases was studied. Results show that, sensitivity of system for SO2 and NO2 are 353 ppb and 963 ppb respectively. It was shown that resonance frequency for Nitrogen, Argon, and Air buffer gases was not noticeably varied by buffer gas pressure increasing, but for Helium, resonance frequency not only is not in range of three other gases, but also grows by pressure increasing. The system noises were damped preparing two buffer chambers.

Mohebbifar, M. R.; Khalilzadeh, J.; Dibaee, B.; Parvin, P.

2014-07-01

12

Quantifying HCHO, NO2 and SO2 Emissions from Industrial Point Sources with 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 petrochemical facilities, such as the greater Houston area, this is particularly challenging as access to facilities is often difficult. Recent modeling studies for Houston suggest that direct emissions of formaldehyde from individual flares play an important role, because HCHO serves as an initial radical precursor which accelerates the degradation of co-emitted hydrocarbons. However, little is known about the emission fluxes of primary HCHO from industrial facilities. It is therefore crucial to develop and deploy novel fence-line remote sensing tools to survey individual pollution sources and visualize pollution plumes of HCHO and other trace gases such as NO2 and SO2. Here we present measurements by a new portable Imaging Differential Optical Absorption Spectrometer (I-DOAS) that was deployed in the Houston area during the FLAIR campaign in the spring/summer of 2009. We performed I-DOAS 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 and SO2 from industrial flares and ship smoke stacks. We will present the methodology of the instrument and show column density images of pollutant plumes. Fluxes from individual flares and smock stacks determined from the I-DOAS measurements vary widely in time and by the emission sources. We observed emissions of up to 15 kg/h for HCHO and 9 kg/h for SO2 from particular sources. We will also discuss how I-DOAS measurements can help to improve estimates of NO2, SO2 and HCHO emission rates from industrial flares and ships.

Pikelnaya, O.; Stutz, J.; Tsai, J.; Fu, D.; Flynn, J. H.; Lefer, B. L.

2010-12-01

13

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.

14

Seasonal characteristics of SO2, NO2, and CO emissions in and around the Indo-Gangetic Plain.  

PubMed

Anthropogenic emissions of sulfur dioxide (SO2), nitrogen dioxide (NO2), and carbon monoxide (CO) exert significant influence on local and regional atmospheric chemistry. Temporal and spatial variability of these gases are investigated using surface measurements by the Central Pollution Control Board (India) during 2005-2009 over six urban locations in and around the Indo-Gangetic Plain (IGP) and supported using the satellite measurements of these gases. The stations chosen are Jodhpur (west of IGP), Delhi (central IGP), Kolkata and Durgapur (eastern IGP), Guwahati (east of IGP), and Nagpur (south of IGP). Among the stations studied, SO2 concentrations are found to be the highest over Kolkata megacity. Elevated levels of NO2 occur over the IGP stations of Durgapur, Kolkata, and Delhi. Columnar NO2 values are also found to be elevated over these regions during winter due to high surface concentrations while columnar SO2 values show a monsoon maximum. Elevated columnar CO over Guwahati during pre-monsoon are attributed to biomass burning. Statistically significant correlations between columnar NO2 and surface NO2 obtained for Delhi, Kolkata, and Durgapur along with very low SO2 to NO2 ratios (?0.2) indicate fossil fuel combustion from mobile sources as major contributors to the ambient air over these regions. PMID:24097012

Mallik, C; Lal, S

2014-02-01

15

Optimal spectral resolution for NO2 and SO2 retrieval by Geostationary Environmental Monitoring Spectrometer (GEMS)  

NASA Astrophysics Data System (ADS)

Ministry of Environment, Korea is planning an environmental geostationary satellite program as a part of MP-GEOSAT (Multi-Purpose GEOstationary SATellite), which is scheduled to be launched in 2017 (Lee S. et al., 2010). It is supposed to be placed on an orbit of approximately 36,000 kilometers high directly over the equator, which revolves in the same direction the earth rotates. Its missions include meteorological, ocean monitoring, and environmental monitoring. Especially, Geostationary Environmental Monitoring Spectrometer (GEMS) is to provide atmospheric chemistry measurements of trace gases such as O3, NO2, SO2, HCHO, and aerosol in high temporal (every 1 hour) and spatial (30x30 km2) resolution over Asia, to monitor regional transport events such as transboundary pollution and Asian dust, and to enhance our understanding on interactions between atmospheric chemistry and meteorology. In order to determine the minimum required spectral resolution of GEMS, measurement accuracy has been estimated for different spectral resolutions based on the actual satellite data as well as model simulation data of very fine spectral resolution. Absorption spectra of SCIAMACHY level 2 data (http://www.temis.nl) with spectral resolution of 0.2nm and reconstructed spectra of broader spectral resolution; 0.4, 0.6, and 0.8nm have been utilized to assess the applicability for SO2 and NO2 retrievals over GEMS spatial coverage areas using the DOAS fitting method. The relative fitting error in SO2 retrieval of each spectral resolution over southern China was determined to be 45.1, 56.1, 99.7, and 187.3 %, respectively. The relative fitting errors in NO2 retrieval of each spectral resolution over northern India were 16.2, 24.6, 32.6, and 38.9 %, respectively. Since relative fitting error in SO2 retrieval increases as the spectra resolution increases, the optimal spectrum resolution was determined to be 0.4nm. On the other hand, since the relative fitting error in NO2 retrieval is below 50 % even for 0.8nm spectral resolution case, spectrum resolution of 0.8nm is thought to be enough for GEMS NO2 monitoring. Additionally, radiance spectra with spectral resolution of 0.2, 0.4, 0.6, and 0.8nm have been simulated by a radiative transfer model, LIDORT (Spurr et al., 2001) over Seoul (37.55 N, 126.98E). In simulations using the LIDORT, US76 atmosphere conditions, aerosol components as OPAC (Hess et al., 1998), surface albedo of 0.2, and aerosol optical depth of 0.02 (up to 2.25 km) were used, assuming 60 degree solar zenith angle, 300 degree solar azimuth angle, 30 degree satellite zenith angle, and 300 degree satellite azimuth angle for the troposphere (Lee K. et al., 2010). Based on the DOAS fit results of both SCIAMACHY data and LIDORT model simulated data, the optimal spectrum resolution for SO2 and NO2 retrieval by GEMS has been determined.

Chong, J.; Kim, Y. J.; Scientific Team of DOAS

2011-12-01

16

The effect of exposure to NO 2 and SO 2 on frost hardiness in Calluna vulgaris  

Microsoft Academic Search

Heather (Callunavulgaris) was grown in pots in a natural heathland soil and exposed in outdoor fumigation chambers (‘solardomes’) to 40 nl l?1 of both nitrogen dioxide (NO2) and sulphur dioxide (SO2) simultaneously. Plants exposed to NO2 and SO2 for 8 months over a growing season (February–November) showed increases in the growth of shoots (+37%) and the whole plant (+15%) and

S. J. M Caporn; T. W Ashenden; J. A Lee

2000-01-01

17

Novel process of simultaneous removal of SO2 and NO2 by sodium humate solution.  

PubMed

A novel simultaneous flue gas desulfurization and denitrification (FGDD) process using sodium humate (HA-Na) solution was proposed. This study relates to the SO2/NO2 absorption efficiency and products of simultaneous removing SO2 and NO2 in a bubbling reactor, especially the effect of recycled water on the SO2/NO2 absorption. Under alkaline conditions, the sulfate content in S-containing compound decreases with the increase of NO2 concentration, whereas there is a contrary result under acidic conditions. Whether the absorption liquid is alkaline or acidic, the presence of NO2 improves the SO2 absorption into HA-Na solution, because NO2 may promote the oxidation of sulfite to sulfate. It seems that the presence of SO2 is unfavorable for the NO2 absorption, but the NO2 absorption efficiency can be improved with the cycle number rising due to the increasing amount of sulfite. Although all the ion concentrations of Na+,SO4(2-),SO3(2-), and NO3- have a gradual increase as the cycle number rises, the ion concentrations of SO4(2-) and Na+ are far more than that of the other ions, which results in a slight decrease of the SO2 absorption efficiency. However, the initial pH of HA-Na solution prepared by recycled water decreases from 10 to 8.1 with the cycle number increasing from 1 to 10, whereas the final pH (the pH after absorption reaction is finished) remains almost constant (3.3). The SO2 absorption efficiency is above 98% and the NO2 absorption efficiency may reach above 95% in the optimal condition in this process. The chief byproduct is a compound fertilizer consisting of humic acid (HA), sulfate, and nitrate. PMID:20704283

Hu, Guoxin; Sun, Zhiguo; Gao, Hanyang

2010-09-01

18

Satellite observations of SO2, NO2, CO, and aerosol over China  

NASA Astrophysics Data System (ADS)

Satellite observations of SO2, NO2, CO, and aerosol over China are related to demographic population density, emissions inventories, industrial production, and thermal power plant geospatial distributions. Similarities and differences in the geospatial distributions of SO2, NO2, CO, and aerosol are identified. Ozone Monitoring Instrument (OMI) SO2 and NO2 atmospheric columns, Measurements of Pollution in the Troposphere (MOPITT) CO columns, and Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depths over China are analyzed during 2005-2007. A comparison of OMI NO2 and University of Columbia gridded population maps indicates a close correspondence between centers of enhanced NO2 and population, with enhanced NO2 and SO2 co-located along the geospatial arc from Shijiazhuang to Luoyang in Hebei, Shanxi, and Henan provinces of China. The region near 35 N and 112 E in northern Henan and southern Shanxi provinces has maxima in NO2, SO2, and CO, which is co-located with power plant number density and population centers. Trends in Global Ozone Monitoring Experiment (GOME) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) NO2 over China from 1996 - 2007, and OMI NO2 from 2004-2008, are compared, and placed in context, to other regions of the world. In accord with previous studies, trends in GOME and SCIAMACHY NO2 over China during 1996-2007 are positive, while trends over Europe and the United States are negative. OMI NO2 columns increase by 8.7 % per year over eastern China (20-30 N, 110-123 E) in the winters of 2004-2008.

Massie, S.; Wu, F.; Krotkov, N.; Levelt, P.; Chu, A.

2009-04-01

19

Degradation of SO 2, NO 2 and NH 3 leading to formation of secondary inorganic aerosols: An environmental chamber study  

NASA Astrophysics Data System (ADS)

We have examined the interactions of gaseous pollutants and primary aerosols that can produce secondary inorganic aerosols. The specific objective was to estimate degradation rates of precursor gases (NH 3, NO 2 and SO 2) responsible for formation of secondary inorganic aerosols. A Teflon-based outdoor environmental chamber facility (volume 12.5 m 3) was built and checked for wall losses, leaks, solar transparency and ability to simulate photochemical reactions. The chamber was equipped with state-of-the-art instrumentation to monitor concentration-time profiles of precursor gases, ozone, and aerosol. A total of 14 experimental runs were carried out for estimating the degradation of precursor gases. The following initial conditions were maintained in the chamber: NO 2 = 246 ± 104 ppb(v), NH 3 = 548 ± 83 ppb(v), SO 2 = 238 ± 107 ppb(v), O 3 = 50 ± 11 ppb(v), PM 2.5 aerosol = 283438 ± 60524 No./litre. The concentration-time profile of gases followed first-order decay and were used for estimating degradation rates (NO 2 = 0.26 ± 0.15 h -1, SO 2 = 0.31 ± 0.17 h -1, NH 3 = 0.35 ± 0.21 h -1). We observed that degradation rates showed a statistical significant positive correlation (at 5% level of significance) with the initial PM 2.5 levels in the chamber (coefficient of correlation: 0.63 for NO 2; 0.62 for NH 3 and 0.51 for SO 2), suggesting that the existing surface of the aerosol could play a significant role in degradation of precursor gases. One or more gaseous species can be adsorbed on to the existing particles and these may undergo heterogeneous or homogeneous chemical transformation to produce secondary inorganic aerosols. Through correlation analysis, we have observed that degradation rates of precursor gases were dependent on initial molar ratio of (NH 3)/(NO 2 + SO 2), indicative of ammonia-rich and ammonia-poor situations for eventual production of ammonium salts.

Behera, Sailesh N.; Sharma, Mukesh

2011-08-01

20

Calculation of pressure-broadened linewidths of SO2 and NO2.  

NASA Technical Reports Server (NTRS)

The Anderson-Tsao-Curnutte theory of line broadening (1949, 1962) is applied to calculate the self-broadened and N2- and O2-broadened linewidths of SO2 and NO2. Computed linewidth values are in good agreement with available experimental results and with calculations by Murphy and Boggs (1967, 1969) on four self-broadened and one nitrogen-broadened lines. Air-broadened linewidths are also calculated for SO2 at 200, 250 and 300 K. The results are considered to be useful for predicting theoretical spectra of SO2 under atmospheric conditions.

Tejwani, G. D. T.

1972-01-01

21

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

22

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

23

Land use patterns and SO2 and NO2 pollution in Ulaanbaatar, Mongolia.  

PubMed

We proposed to study spatial distribution and source contribution of SO2 and NO2 pollution in Ulaanbaatar, Mongolia. We collected 2-week ambient SO2 and NO2 concentration samples at 38 sites, which were classified by major sources of air pollution such as ger areas and/or major roads, in three seasons as warm (September, 2011), cold (November-December, 2011), and moderate (March, 2012) in Ulaanbaatar. The SO2 and NO2 concentrations were collected by Ogawa ambient air passive samplers and analyzed by ion chromatography and spectrophotometry methods, respectively. Stepwise regression models were used to estimate the contribution of emission proxies, such as the distance to major roads, ger areas, power plants, and city center, to the ambient concentrations of SO2 and NO2. We found that the SO2 and NO2 concentrations were significantly higher in the cold season than in the warm and moderate seasons at all 38 ambient sampling sites. The SO2 concentrations in 20 ger sites (46.60 ppb in the cold season and 17.82 ppb in the moderate season) were significantly higher than in 18 non-ger sites (23.35 ppb in the cold season and 12.53 ppb in the moderate season). The NO2 concentrations at 19 traffic/road sites (12.85 ppb in the warm season and 20.48 ppb in the moderate season) were significantly higher than those at 19 urban sites (7.60 ppb and 14.39 ppb in the moderate season). Multiple regression models show that SO2 concentrations decreased by 23% in the cold and 17% in the moderate seasons at 0.70 km from the ger areas, an average of all sampling sites, and by 29% in the moderate season at 4.83 km from the city center, an average of all sampling sites. Multiple regression models show that the NO2 concentrations at 4.83 km from the city center decreased by 38% in the warm and 29% in the moderate seasons. Our models also report that NO2 concentrations at 0.16 km from the main roads decreased by 15% and 9% in the warm and the moderate seasons, respectively, and by 16% in the cold season decreased at the location 0.70 km from the ger area. The NO2 concentration at the location 4.83 km from the city center was decreased by 18% and at the location 4.79 km from the power plants by 21%. Our study concludes that SO2 and NO2 concentrations are very high in Ulaanbaatar, especially in the winter, and can be explained by several land use variables, including the distance to the ger areas, the city center, the main roads, and the power plants. PMID:23522614

Huang, Yu-Kai; Luvsan, Munkh-Erdene; Gombojav, Enkhjargal; Ochir, Chimedsuren; Bulgan, Jargal; Chan, Chang-Chuan

2013-07-01

24

The enhanced oxidation of SO2 by NO2 on carbon particulates  

NASA Technical Reports Server (NTRS)

The oxidation of SO2 on carbon particles in dry air and in air at 65% relative humidity (RH) was found to be greatly enhanced by the presence of gaseous NO2. Exposures of 20-80ppm SO2 + 10ppm NO2 on 1-mg samples of commercial carbon black were found to produce both sorption and desorption coverages (weight retained after desorption into N2) of over one order of magnitude greater than for corresponding SO2 exposures. Significant agglomeration and wetting were observed to occur progressively during exposures at 65% RH, and samples, even after 150-h exposure, rarely reached steady-state weight gain. The wetting may have regenerated fresh reactive carbon surface. Sorptions conducted in nitrogen atmospheres, rather than in air, appeared to produce slightly higher sorptions and weight retentions for equivalent exposure concentrations and times, indicating that NO2 served as the oxidizer and that molecular oxygen, or some trace constitutents in air, may have weakly inhibited the oxidation by NO2. Wet chemical analysis of the desorbed phase indicated that sulfate, presumably H2SO4 accounted for over half of the retained weight. Measurements of pH from water-quenched samples indicated a highly acidic surface phase, and suggested the oxidation process could proceed in an acidic environment.

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

1980-01-01

25

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

26

Mobile SO2 and NO2 DIAL Lidar system for enforcement use  

Microsoft Academic Search

A self-contained mobile differential absorption lidar (DIAL) system intended for measuring SO2 and NO2 concentrations from stationary combustion sources has been completed for enforcement use. The system uses tunable Ti:sapphire laser technology, with nonlinear conversion to the blue and UV absorption wavelengths. Separate tunable laser oscillators at slightly offset wavelengths are pumped on alternate pulses of a 20 Hz doubled

David L. Cunningham; William H. Pence; Stephen E. Moody

1994-01-01

27

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

28

Air quality over the Alberta oil sands: Satellite observations of NO2 and SO2  

NASA Astrophysics Data System (ADS)

A vast reserve of bitumen - oil mixed with sand, clay, and water generally referred to as oil sands - resides in northern Alberta, Canada. Extraction of bitumen and its upgrade to liquid fuel is very energy intensive and generates significant emissions, including nitrogen and sulphur oxides. Satellite observations of NO2 and SO2 vertical column densities have been used to assess the magnitude and distribution of these pollutants throughout the oil sands. Preliminary results indicate a statistically significant enhancement in both species over an area (~30 x 30 km2) of intensive surface mining. Quantifying the burden of these enhancements and their recent changes over such a small area, comparable to the resolution of the best air quality satellite instruments, represents a significant challenge. The methodology used to meet this challenge will be presented, as will initial results including trends over the past decade, comparisons with other large industrial operations, and an assessment of consistency with emission inventories.

McLinden, C. A.; Fioletov, V.

2011-12-01

29

Carbon catalysis in the aqueous oxidation of SO2 by NO2 and air  

NASA Technical Reports Server (NTRS)

Sulfur dioxide and an oxidant gas (air or NO2) were bubbled through aqueous suspensions of both washed and unwashed carbon black as well as through samples of wash water, which contained whatever soluble species were originally present on the carbon, and high-purity water. The sulfate yields obtained showed the washed and unwashed carbon to be equally catalytic for the oxidation of SO2 to sulfate by both oxidants, whereas little sulfate was generated in either the wash water or high-purity water in the absence of carbon. These results indicate that the sulfate yields produced in aqueous suspensions of the carbon studied are due to catalysis by the carbon particles rather than by soluble species dissolved from them.

Schryer, D. R.; Schryer, J.; Cofer, W. R., III; Vay, S. A.

1984-01-01

30

The influence of SO2 and NO2 impurities on CO2 gas hydrate formation and stability.  

PubMed

The sequestration of industrially emitted CO(2) in gas hydrate reservoirs has been recently discussed as an option to reduce atmospheric greenhouse gas. This CO(2) contains, despite much effort to clean it, traces of impurities such as SO(2) and NO(2) . Here, we present results of a pilot study on CO(2) hydrates contaminated with 1% SO(2) or 1% NO(2) and show the impact on hydrate formation and stability. Microscopic observations show similar hydrate formation rates, but an increase in hydrate stability in the presence of SO(2). Laser Raman spectroscopy indicates a strong enrichment of SO(2) in the liquid and hydrate phase and its incorporation in both large and small cages of the hydrate lattice. NO(2) is not verifiable by laser Raman spectroscopy, only the presence of nitrate ions could be confirmed. Differential scanning calorimetry analyses show that hydrate stability and dissociation enthalpy of mixed CO(2)-SO(2) hydrates increase, but that only negligible changes arise in the presence of NO(2) impurities. X-ray diffraction data reveal the formation of sI hydrate in all experiments. The conversion rates of ice+gas to hydrate increase in the presence of SO(2), but decrease in the presence of NO(2). After hydrate dissociation, SO(2) and NO(2) dissolved in water and form strong acids. PMID:21433127

Beeskow-Strauch, Bettina; Schicks, Judith M; Spangenberg, Erik; Erzinger, Jörg

2011-04-11

31

Inorganic Liquids for Removing SO2 from Flue Gases. Phase I.  

National Technical Information Service (NTIS)

A literature survey was performed to determine the applicability of inorganic liquids to the development of new processes for removing SO2 from flue gases. Inorganic liquids have the potential for absorbing SO2 at flue gas temperatures sufficiently high t...

F. Tepper J. S. Greer W. J. Cooper E. Goldberg F. G. Prado

1969-01-01

32

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

33

Concentrations, distributions and critical level exceedance assessment of SO2, NO2 and O3 in South Africa.  

PubMed

South Africa has been identified as a source of industrial pollution that is significant at a global scale. This study was designed to provide quantitative information, by direct measurement, across northeastern South Africa, which includes the highly industrialised Mpumalanga Highveld. The specific aim of the study was to evaluate whether or not acidic atmospheric pollution poses a threat to soils, plants and water bodies of South Africa. To address this aim, a network of 37 passive sampling sites was established to measure monthly mean concentrations of near-surface SO(2), NO(2) and ozone. The area covered extended over the northern and eastern interior of South Africa while avoiding sources of local emissions such as towns, mines and highways. The field campaign was conducted between August 2005 and September 2007. Spatial distributions and temporal trends for these pollutant gases were assessed. Critical levels analysis comparisons were made against applicable air quality standards, guidelines and limits to evaluate the potential for adverse atmospheric pollution impacts on regional environments. The assessment indicates that only in the central source area of the South African industrial Highveld are some levels exceeded. In remote areas, including the sensitive forested regions of the Drakensberg escarpment, pollutant concentrations are below the critical thresholds for environmental damage. PMID:20024614

Josipovic, Miroslav; Annegarn, Harold J; Kneen, Melanie A; Pienaar, Jacobus J; Piketh, Stuart J

2010-12-01

34

Synergistic reaction between SO2 and NO2 on mineral oxides: a potential formation pathway of sulfate aerosol.  

PubMed

Sulfate is one of the most important aerosols in the atmosphere. A new sulfate formation pathway via synergistic reactions between SO(2) and NO(2) on mineral oxides was proposed. The heterogeneous reactions of SO(2) and NO(2) on CaO, ?-Fe(2)O(3), ZnO, MgO, ?-Al(2)O(3), TiO(2), and SiO(2) were investigated by in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) at ambient temperature. Formation of sulfate from adsorbed SO(2) was promoted by the coexisting NO(2), while surface N(2)O(4) was observed as the crucial oxidant for the oxidation of surface sulfite. This process was significantly promoted by the presence of O(2). The synergistic effect between SO(2) and NO(2) was not observed on other mineral particles (such as CaCO(3) and CaSO(4)) probably due to the lack of the surface reactive oxygen sites. The synergistic reaction between SO(2) and NO(2) on mineral oxides resulted in the formation of internal mixtures of sulfate, nitrate, and mineral oxides. The change of mixture state will affect the physicochemical properties of atmospheric particles and therefore further influence their environmental and climate effects. PMID:21993907

Liu, Chang; Ma, Qingxin; Liu, Yongchun; Ma, Jinzhu; He, Hong

2012-02-01

35

Observations of SO2 and NO2 by mobile DOAS in the Guangzhou eastern area during the Asian Games 2010  

NASA Astrophysics Data System (ADS)

Mobile passive differential optical absorption spectroscopy measurements of SO2 and NO2 were performed in the Guangzhou eastern area (GEA) during the Guangzhou Asian Games 2010 from November 2010 to December 2010. The observations were carried out between 10:00 to 13:00 (local time, i.e., during daylight). Spatial and temporal distributions of SO2 and NO2 in this area were obtained and emission sources were determined using wind field data. The NO2 vertical column densities were found to agree with Ozone Monitoring Instrument values. The correlation coefficient (referred to as R2) was 0.88 after cloud filtering within a specific ground pixel. During the Guangzhou Asian Games and Asian Paralympics (Para) Games, the SO2 and NOx emissions in the area were quantified using averaged wind speed and wind direction. For times outside the games the average SO2 emission was estimated to be 9.50 ± 0.90 tons per hour and the average NOx emission was estimated to be 5.87 ± 3.46 tons per hour. During the phases of the Asian and Asian Para Games, the SO2 and NOx emissions were reduced by 53.50% and 43.50%, respectively, compared to the usual condition. We also investigated the influence of GEA on Guangzhou University Town, the main venue located northwest of the GEA, and found that SO2 concentrations here were about tripled by emissions from the GEA.

Wu, F. C.; Xie, P. H.; Li, A.; Chan, K. L.; Hartl, A.; Wang, Y.; Si, F. Q.; Zeng, Y.; Qin, M.; Xu, J.; Liu, J. G.; Liu, W. Q.; Wenig, M.

2013-09-01

36

Thermal Stability of SO2- and NO2 Adsorbed on the Surface of Sepiolite, a Porous Clay Mineral  

NASA Astrophysics Data System (ADS)

Nitrogen dioxide (NO2) and sulfur dioxide (SO2) adsorbed on the surface (sub-basket) of a porous clay mineral of sepiolite (Mg4Si6O15(OH)2\\cdot 6H2O) at room temperature were studied in terms of ESR signals after ?-ray irradiation at 77 K. Molecular radical species were observed with the anisotropic g-factors of gx=2.0055, gy=1.9921 and gz=2.0020 and hyperfine splitting constants of Ax=5.25 mT, Ay=4.90 mT and Az=6.49 mT for NO2, and g\\|=2.0093 and g\\bot=2.0024 for SO2-. The activation energies and frequency factors for thermal annealing of NO2 adsorbed on as-received sepiolite and HCl-treated sepiolite are 0.23 eV, 2.2× 104 s-1 and 0.25 eV, 4.7× 104 s-1, respectively. The NO2 signal was thermally annealed at temperatures up to 200 K. A different property of NO2 signal as that in solid NO2 was observed in a more concentrated NO2 gas adsorbed on sepiolite. A paramagnetic SO2- signal was observed during the annealing experiment at 260 K.

Matsuda, Tokiyoshi; Ikeya, Motoji

2002-05-01

37

State-of-the art Differential Absorption and Scattering (DAS) lidar for SO2 and NO2  

NASA Technical Reports Server (NTRS)

A ground-based laser remote sensing system for the range-resolved detection of sulfur dioxide and nitrogen dioxide is described. The measurement is based on the differential absorption and scattering lidar technique. Both lasers are fired with a fixed time delay of 50 microsec to probe an atmosphere with unchanged optical properties. The NO2 is detected with two dye lasers emitting arouns 450 nm; SO2 is measured at 300 nm with the frequency-doubled output of two dye lasers. Field measurements in a city are presented. Determinations of SO2 emission rates from a smokestack agree well with operator data.

Lahmann, W.; Staehr, W.; Weitkamp, C.; Michaelis, W.

1984-01-01

38

Improved satellite retrievals of NO2 and SO2 over the Canadian oil sands and comparisons with surface measurements  

NASA Astrophysics Data System (ADS)

Satellite remote sensing is increasingly being used to monitor air quality over localized sources such as the Canadian oil sands. Following an initial study, significantly low biases have been identified in current NO2 and SO2 retrieval products from the Ozone Monitoring Instrument (OMI) satellite sensor over this location resulting from a combination of its rapid development and small spatial scale. Air mass factors (AMFs) used to convert line-of-sight "slant" columns to vertical columns were re-calculated for this region based on updated and higher resolution input information including absorber profiles from a regional-scale (15 km × 15 km resolution) air quality model, higher spatial and temporal resolution surface reflectivity, and an improved treatment of snow. The overall impact of these new Environment Canada (EC) AMFs led to substantial increases in the peak NO2 and SO2 average vertical column density (VCD), occurring over an area of intensive surface mining, by factors of 2 and 1.4, respectively, relative to estimates made with previous AMFs. Comparisons are made with long-term averages of NO2 and SO2 (2005-2011) from in situ surface monitors by using the air quality model to map the OMI VCDs to surface concentrations. This new OMI-EC product is able to capture the spatial distribution of the in situ instruments (slopes of 0.65 to 1.0, correlation coefficients of >0.9). The concentration absolute values from surface network observations were in reasonable agreement, with OMI-EC NO2 and SO2 biased low by roughly 30%. Several complications were addressed including correction for the interference effect in the surface NO2 instruments and smoothing and clear-sky biases in the OMI measurements. Overall these results highlight the importance of using input information that accounts for the spatial and temporal variability of the location of interest when performing retrievals.

McLinden, C. A.; Fioletov, V.; Boersma, K. F.; Kharol, S. K.; Krotkov, N.; Lamsal, L.; Makar, P. A.; Martin, R. V.; Veefkind, J. P.; Yang, K.

2014-04-01

39

Compilation of tables of surface deposition velocities for O 3, NO 2 and SO 2 to a range of indoor surfaces  

NASA Astrophysics Data System (ADS)

Surface deposition velocities of O 3, NO 2 and SO 2 were measured in chamber experiments at relative air humidity ranging from 0% to 90% and obtained from literature screening, for a range of material surfaces typically found indoors. The data were compiled in tables comprising 24 material classes and five values of relative air humidity for each gas. Interpolation between data points and extrapolation based on measurements on similar materials were used to fill in the tables where values from measurement were lacking. The tabulated values should be useful in estimating indoor concentrations of these gases when outdoor concentrations are known and there are no indoor sources.

Grøntoft, Terje; Raychaudhuri, Michele R.

40

Interaction of copper and NO 2: Effect of joint presence of SO 2, relative humidity and temperature  

Microsoft Academic Search

This paper reports laboratory tests involving the dry deposition on copper surfaces of NO2, alone and in combination with SO2, at different concentrations (200 and 800?gm?3), temperatures (15, 25 and 35°C) and relative humidities (50%, 70% and 90%). Gravimetric results and characterisation of the corrosion products by optical microscopy, scanning electron microscopy (SEM\\/EDX), grazing incidence X-ray diffraction (GIXD) and X-ray

L. Mariaca; D. de la Fuente; S. Feliu Jr.; J. Simancas; J. A. González; M. Morcillo

2008-01-01

41

Ground based measurements of SO2 and NO2 emissions from the oil refinery "la Teja" in Montevideo city  

NASA Astrophysics Data System (ADS)

We present preliminary results of ground based measurements of SO2 and NO2 emissions from "La Teja" oil refinery located in the northern part of Montevideo Bay. Our study is part of a long term effort to localize and monitor relevant emission sources in the city area of Montevideo. These measurements were performed with a Miniature Multi AXis Differential Optical Absorption Spectrometry (MiniMAX-DOAS) instrument, which is basically a temperature controlled medium-resolution spectrometer (~ 0.5 nm) equipped with a small telescope and a stepper motor allowing automatic scans in one dimension. We present a discussion about the evolution and transformation of both above species in the atmosphere. Our observation site was approximately 1.9 km away from the oil refinery and we were able to perform vertical and horizontal scans of the plume emitted (during our measurements) almost horizontally from its stacks. The maximum value of the SO2 slant column density (SCD) was found to be ~ 4×1017 molec cm-2 directly over the oil refinery, decreasing as the plume disperses. In contrast, the NO2 SCD peaks at ~ 1×1016 molec cm-2 directly over the source and increases continuously as the plume disperses. The SO2 flux measured immediately downwind of the refinery was found to be about 1200 kg h-1 (±40% uncertainty).

Frins, Erna; Ibrahim, Ossama; Casaballe, Nicolás; Osorio, Matías; Arismendi, Federico; Wagner, Thomas; Platt, Ulrich

2011-01-01

43

Comparing different light-emitting diodes as light sources for long path differential optical absorption spectroscopy NO2 and SO2 measurements  

NASA Astrophysics Data System (ADS)

In this paper, we present a comparison of different light-emitting diodes (LEDs) as the light source for long path differential optical absorption spectroscopy (LP-DOAS) atmospheric trace gas measurements. In our study, we use a fiberoptic design, where high power LEDs used as the light source are coupled into the telescope using a Y shape fiber bundle. Two blue and one ultraviolet (UV) LEDs with different emission wavelength ranges are tested for NO2 and SO2 measurements. The detailed description of the instrumental setup, the NO2 and SO2 retrieval procedure, the error analysis, and the preliminary results from the measurements carried out in Science Island, Hefei, Anhui, China are presented. Our first measurement results show that atmospheric NO2 and SO2 have strong temporal variations in that area and that the measurement accuracy is strongly dependent on the visibility conditions. The measured NO2 and SO2 data are compared to the Ozone Monitoring Instrument (OMI) satellite observations. The results show that the OMI NO2 product underestimates the ground level NO2 by 45%, while the OMI SO2 data are highly influenced by clouds and aerosols, which can lead to large biases in the ground level concentrations. During the experiment, the mixing ratios of the atmospheric NO2 and SO2 vary from 8 ppbv to 36 ppbv and from 3 ppbv to 18 ppbv, respectively.

Chan, Ka-Lok; Ling, Liu-Yi; Andreas, Hartl; Zheng, Ni-Na; Gerrit, Kuhlmann; Qin, Min; Sun, You-Wen; Xie, Pin-Hua; Liu, Wen-Qing; Mark, Wenig

2012-11-01

44

Coal fly ash based carbons for SO 2 removal from flue gases  

Microsoft Academic Search

Two different coal fly ashes coming from the burning of two coals of different rank have been used as a precursor for the preparation of steam activated carbons. The performance of these activated carbons in the SO2 removal was evaluated at flue gas conditions (100°C, 1000ppmv SO2, 5% O2, 6% H2O). Different techniques were used to determine the physical and

B. Rubio; M. T. Izquierdo

2010-01-01

45

Coal fly ash based carbons for SO2 removal from flue gases.  

PubMed

Two different coal fly ashes coming from the burning of two coals of different rank have been used as a precursor for the preparation of steam activated carbons. The performance of these activated carbons in the SO(2) removal was evaluated at flue gas conditions (100 degrees C, 1000 ppmv SO(2), 5% O(2), 6% H(2)O). Different techniques were used to determine the physical and chemical characteristics of the samples in order to explain the differences found in their behaviour. A superior SO(2) removal capacity was shown by the activated carbon obtained using the fly ash coming from a sub-bituminous-lignite blend. Experimental results indicated that the presence of higher amount of certain metallic oxides (Ca, Fe) in the carbon-rich fraction of this fly ash probably has promoted a deeper gasification in the activation with steam. A more suitable surface chemistry and textural properties have been obtained in this case which explains the higher efficiency shown by this sample in the SO(2) removal. PMID:20167465

Rubio, B; Izquierdo, M T

2010-07-01

46

Simultaneous Treatment of SO2 Containing Stack Gases and Waste Water.  

National Technical Information Service (NTIS)

A process is described for simultaneously removing sulfur dioxide from stack gases and the like, and for purifying waste water such as derived from domestic sewage. A portion of the gas stream and a portion of the waste water, the latter containing dissol...

J. C. Poradek D. D. Collins

1978-01-01

47

Studies of Chemiluminescence in Boron Atom Reactions with O2, SO2, N2O, NO2 and H2O2.  

National Technical Information Service (NTIS)

Chemiluminescence has been observed in the single collision reactions of boron atoms with O2, SO2, N2O, NO2, and H2O2. Experiments were performed in a beam-gas apparatus using photon counting to detect the optical signals. The electronically excited ((A s...

J. DeHaven M. T. O'Connor P. Davidovits

1980-01-01

48

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

49

Fourier Transform Infrared (FT-IR) Spectroscopy of Atmospheric Trace Gases HCl, NO and SO2  

NASA Technical Reports Server (NTRS)

Fourier Transform Infrared (FT-IR) spectral data have been recorded in the spectral region 400-4000/cm of hydrogen chloride and sulfur dioxide with I/cm resolution and of nitric oxide with 0.25 cm-i resolution, under quasi-static conditions, when the sample gas was passed through tubings of aluminum, copper, stainless steel and teflon. The absorbance was measured for the rotational lines of the fundamental bands of (1)H(35)Cl and (1)H(37)Cl for pressures in the range 100-1000 Torr and for the (14)N(16)O molecule in the range 100-300 Torr. The absorbance was also measured for individual rotational lines corresponding to the three modes of vibrations (upsilon(sub 1) - symmetric stretch, upsilon(sub 2) - symmetric bend, upsilon(sub 3) - anti-symmetric stretch) of the SO2 molecule in the pressure range 25-150 Torr. A graph of absorbance versus pressure was plotted for the observed rotational transitions of the three atmospherically significant molecules, and it was found that the absorbance was linearly proportional to the pressure range chosen, thereby validating Beer's law. The absorption cross-sections were determined from the graphical slopes for each rotational transition recorded for the HCl, NO and SO2 species. Qualitative and quantitative spectral changes in the FT-IR data will be discussed to identify and characterize various tubing materials with respect to their absorption features.

Haridass, C.; Aw-Musse, A.; Dowdye, E.; Bandyopadhyay, C.; Misra, P.; Okabe, H.

1998-01-01

50

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

51

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

52

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

53

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

54

Kinetics of CH2OO reactions with SO2, NO2, NO, H2O and CH3CHO as a function of pressure.  

PubMed

Kinetics of CH2OO Criegee intermediate reactions with SO2, NO2, NO, H2O and CH3CHO and CH2I radical reactions with NO2 are reported as a function of pressure at 295 K. Measurements were made under pseudo-first-order conditions using flash photolysis of CH2I2-O2-N2 gas mixtures in the presence of excess co-reagent combined with monitoring of HCHO reaction products by laser-induced fluorescence (LIF) spectroscopy and, for the reaction with SO2, direct detection of CH2OO by photoionisation mass spectrometry (PIMS). Rate coefficients for CH2OO + SO2 and CH2OO + NO2 are independent of pressure in the ranges studied and are (3.42 ± 0.42) × 10(-11) cm(3) s(-1) (measured between 1.5 and 450 Torr) and (1.5 ± 0.5) × 10(-12) cm(3) s(-1) (measured between 25 and 300 Torr), respectively. The rate coefficient for CH2OO + CH3CHO is pressure dependent, with the yield of HCHO decreasing with increasing pressure. Upper limits of 2 × 10(-13) cm(3) s(-1) and 9 × 10(-17) cm(3) s(-1) are placed on the rate coefficients for CH2OO + NO and CH2OO + H2O, respectively. The upper limit for the rate coefficient for CH2OO + H2O is significantly lower than has been reported previously, with consequences for modelling of atmospheric impacts of CH2OO chemistry. PMID:24287566

Stone, Daniel; Blitz, Mark; Daubney, Laura; Howes, Neil U M; Seakins, Paul

2014-01-21

55

Flux Emissions of SO2 and NO2 Measured at the Tula Industrial Complex (Mexico) during MCMA 2006 Field Campaign using a Mini-DOAS System  

NASA Astrophysics Data System (ADS)

The Tula industrial zone is located 60 km northeast from the Mexico City Metropolitan Area (MCMA), in the Hidalgo State in México. This region is known as the Tula-Vito-Apasco industrial corridor, where a number of industries are located. According to the latest information from the environmental authority, about 313,000 ton/year of SO2 and 40,000 ton/year of NOx are released in this region. The Miguel Hidalgo refinery (MHR) and the Francisco Pérez Ríos power plant (FPRPP) are the main emitters, contributing almost 90% of SO2 and 80% of NOx from the total emission inside the Hidalgo State. Other industries such as cement plants, open-sky mines and agricultural activities are also responsible for important emissions of particulat matter (PM) into the atmosphere and soil erosion. This highly industrialized region is thought to influence the air quality in the MCMA, where in some occasions SO2 concentrations in the north part of the city have exceeded the Mexican air quality standard (130 ppb as a 24 hour average), which could not be attributed to irregular operations of industries located in the surrounding area. To address the question of emissions from the refinery and the power plant, the total fluxes of SO2 and NO2 were determined by measurements of their respective integrated vertical column in the neighborhood of the Tula industrial zone, using a Mini-DOAS system. These measurements were carried out as part of the MCMA-2006/MILAGRO Field Campaign, from March 24th to April 18th 2006. Meteorological measurements at the height of the plume dispersion were also determined using pilot balloons and radiosondes techniques. The experimental data were complemented by model simulations. Forward Lagrangian stochastic trajectories were calculated to simulate the plume using FLEXPART in combination with meso-scale meteorological simulations with MM5. The experimental data set was used to evaluate model performance. The simulations were used as an additional estimate of plume transport speeds. Potential air quality impacts on the MCMA were simulated. These were verified by combining surface SO2 measurements in the basin with backward trajectories, thereby providing a means of discriminating the urban impacts of different potential source regions.

Sosa, G.; Rivera, C.; Wöhrnschimmel, H.; de Foy, B.; Johansson, M.; Molina, L. T.

2007-05-01

56

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)

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

57

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.

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

2013-01-01

58

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

59

Aerosol optical depth, backscattering profiles and column NO2 and SO2 measurements during March 2006 in Tenango del Aire, Mexico.  

NASA Astrophysics Data System (ADS)

The Tenango del Aire site (19.16°N, 98.86°W, 2380 masl) is located some 40 km SE from Mexico City in the Chalco Valley, where some pollution otflow has been predicted by air quality models. Direct and diffuse ground-based irradiance measurements have been made at this site during the MILAGRO field campaign by a UV-MultiFilter Rotating ShadowBand Radiometer (UV-MFRSR) at seven channels (300-, 305-, 311-, 317-, 325-, 332- and 368-nm with 2-nm nominal bandpass) from which several parameters could be calculated, including the aerosol optical depths (AOD), total ozone column (TOC), asymmetry factor (g) and aerosol single scattering albedo (SSA) via an optimal estimation algorithm. NO2 and SO2 column concentrations were measured with the zenith-sky DOAS (differential absorption spectrometer) technique. LIDAR (light detection and ranging) remote sensing of aerosols was done with a Vaisala Ceilometer Model LD40 from which mixing layer heights were estimated. The results of these measurements and a preliminary analysis of the possible sources of the aerosols are presented.

Hernandez, A.; Basaldud, R.; Grutter, M.; Baumgardner, D.; Slusser, J.; Steinbrecher, R.; Ruiz-Suarez, L. G.

2007-05-01

60

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

61

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

62

DOAS for flue gas monitoring—II. Deviations from the Beer-Lambert law for the U.V.\\/visible absorption spectra of NO, NO 2, SO 2 and NH 3  

Microsoft Academic Search

Deviations from the Beer-Lambert law were studied for the differential absorption cross-sections for NO, SO2, NO2 and NH3. This was performed by simple calculations, computer simulations of spectra and by recordings of spectra for the above mentioned species at various total columns. The linearity studies for the DOAS instrument displayed large variations for the molecules studied and for different wavelength

Johan Mellqvist; Arne Rosén

1996-01-01

63

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?).

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

2010-01-01

64

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

65

Effects of Various Parameters on Removal of NO2 Gases in Fixed Beds by Adsorption on Sepiolite  

Microsoft Academic Search

Removal of NO2 gases in fixed beds was investigatedby using brownish, whitish and regenerated whitish sepioliteand perlite as adsorbents. For this purpose, NO2 wasproduced by reaction of copper with nitric acid. The producedgas was mixed with air and the mixture was sent through a fixedbed. Studies were conducted using various gas flow rates,NO2 concentrations, packing sizes and heights of bed.Remaining

Atilla Murathan; Ahmet Biçer; Ahmet Alicilar; Ayse Murathan

2001-01-01

66

Combined NOx/SO2 Control Technology.  

National Technical Information Service (NTIS)

Commercially available technology for the removal of both NOx and SO2 from flue gases generally involves separate systems for each pollutant. Current research and development efforts emphasize integrated technologies that combine NOxSO2(and perhaps partic...

C. D. Livengood

1989-01-01

67

Evaluation of gases, condensates, and SO 2 emissions from Augustine volcano, Alaska: the degassing of a Cl-rich volcanic system  

Microsoft Academic Search

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

Robert B Symonds; William I Rose; Terrence M Gerlach; Paul H Briggs; Russell S Harmon

1990-01-01

68

40 CFR 60.4330 - What emission limits must I meet for sulfur dioxide (SO2)?  

Code of Federal Regulations, 2010 CFR

...from the affected source any gases that contain SO 2 in excess...not have access to natural gas and that the removal of sulfur compounds would cause more environmental...stationary combustion turbine any gases which contain SO 2...

2009-07-01

69

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

70

Harmonization of Methods for Measurements of SO2.  

National Technical Information Service (NTIS)

The aim of this contract was a study of the applicability of SO2 calibration gases in steel cylinders for the calibration and intercomparison of different instrumental methods of measuring ambient SO2 levels. The study was carried out in three steps: A pr...

E. P. Muylle H. J. Peperstraete

1982-01-01

71

Flux Calculation Using CARIBIC DOAS Aircraft Measurements: SO2 Emission of Norilsk  

NASA Technical Reports Server (NTRS)

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-Schoech, A.; Brenninkmeijer, C. A. M.; Lamsal, L. N.; Krotkov, N. A.; Platt, U.

2012-01-01

72

SO 2 sorption on fresh and aged SO x traps  

Microsoft Academic Search

This study has an important impact on gasoline engine-pollution control working under lean conditions. While NOx trap systems can remove NOx under an oxidative atmosphere, they are poisoned by SOx present in the exhaust gases. In order to protect NOx traps, an upstream SOx trap has to be used. SO2 adsorption was studied in the presence of water and oxygen.

L Limousy; H Mahzoul; J. F Brilhac; P Gilot; F Garin; G Maire

2003-01-01

73

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

74

40 CFR 60.4330 - What emission limits must I meet for sulfur dioxide (SO2)?  

Code of Federal Regulations, 2010 CFR

...from the affected source any gases that contain SO2 in excess...not have access to natural gas and that the removal of sulfur compounds would cause more environmental...stationary combustion turbine any gases which contain SO2 in...

2010-07-01

75

Development of Combustion Data to Utilize Low-Btu Gases as Industrial Process Fuels. Project 8985 Special Report No. 2, Kiln Burner.  

National Technical Information Service (NTIS)

Data were gathered to determine the performance of a kiln burner when retrofit with three low-Btu gases. The burner was fired on the IGT pilot-scale test furnaces with a load simulating the calcining and reaction zones of a cement kiln. The low- and mediu...

R. T. Waibel E. S. Fleming

1978-01-01

76

Novel process for simultaneous removal of NO(x) and SO2 from simulated flue gas by using a sustainable Ag(I)/Ag(II) redox mediator.  

PubMed

The objective of this work is to develop a sustainable process for simultaneous removal of waste gases such as NO, NO2, and SO2 by an electrochemically generated Ag(I)/Ag(II) redox mediator system. High removal efficiency was achieved for NO and SO2 by the wet scrubbing method at room temperature and atmospheric pressure. This removal is achieved through oxidation and absorption by contacting the gaseous stream with redox mediator ions that offer specific or selective solubility for the solute gases to be recovered in a wet scrubber. The process parameters such as gas velocity, liquid velocity, Ag(I) concentration, and HNO3 concentration were investigated to explore the possibility of complete removal of waste gases. The Ag(I)/Ag(II)-based mediated electrochemical oxidation process proved to be quite effective for simultaneous removal of NO, NO(x), and SO2 from the simulated flue gas mixtures containing NO and SO2 over a wide concentration range of 100-400 ppm. Studies were carried out with individual gas components for the mixture, and the effect of input NO and input SO2 concentrations on the NO(x) and SO2 removal efficiencies at 20 degrees C was examined. Complete oxidation of NO to NO2 with 100% NO removal efficiency and 92% NO(x) removal efficiency was achieved along with 100% SO2 removal efficiency, highlighting a potentially far greater efficiency of the Ag(I)/Ag(II)-based system in functionality and selectivity. Active research work in this direction is anticipated in the near future. PMID:18939587

Raju, Thasan; Chung, Sang Joon; Moon, Il Shik

2008-10-01

77

SO2 depletion in tropospheric volcanic plumes  

NASA Astrophysics Data System (ADS)

Ground based remote sensing techniques are used to measure volcanic SO2 fluxes in efforts to characterise volcanic activity. As these measurements are made several km from source there is the potential for in-plume chemical transformation of SO2 to sulphate aerosol (conversion rates are dependent on meteorological conditions), complicating interpretation of observed SO2 flux trends. In contrast to anthropogenic plumes, SO2 lifetimes are poorly constrained for tropospheric volcanic plumes, where the few previous loss rate estimates vary widely (from $\\ll$1 to >99% per hour). We report experiments conducted on the boundary layer plume of Masaya volcano, Nicaragua during the dry season. We found that SO2 fluxes showed negligible variation with plume age or diurnal variations in temperature, relative humidity and insolation, providing confirmation that remote SO2 flux measurements (typically of ~500-2000 s old plumes) are reliable proxies for source emissions for ash free tropospheric plumes not emitted into cloud or fog.

McGonigle, A. J. S.; Delmelle, P.; Oppenheimer, C.; Tsanev, V. I.; Delfosse, T.; Williams-Jones, G.; Horton, K.; Mather, T. A.

2004-07-01

78

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

79

Mechanism of SO2 removal by carbon  

USGS Publications Warehouse

The reaction of SO2 with carbon (C) in the presence of O2 and H2O involves a series of reactions that leads to the formation of sulfuric acid as the final product. The rate-determining step in the overall process is the oxidation of SO2 to SO3. Three SO2 oxidation reactions are possible. Adsorbed SO2 (C-SO2) can react either with gas phase O2 or with adsorbed oxygen (C-O complex) to form sulfur trioxide (SO3), or gas phase SO2 can react directly with the C-O complex. In optimizing the SO2 removal capabilities of carbon, most studies only assume a given mechanism for SO2 adsorption and conversion to H2SO4 to be operable. The appropriate SO2 oxidation step and role of the C-O complex in this mechanism remain to be determined. The ultimate goal of this study was to prepare activated char from Illinois coal with optimal properties for low-temperature (80-150 ??C) removal of sulfur dioxide from coal combustion flue gas. The SO2 adsorption capacity of activated char was found to be inversely proportional to the amount of oxygen adsorbed on its surface. A temperature-programmed desorption technique was developed to titrate those sites responsible for adsorption of SO2 and conversion to H2SO4. On the basis of these results, a mechanism for SO2 removal by carbon was proposed. The derived rate expression showed SO2 adsorption to be dependent only on the fundamental rate constant and concentration of carbon atoms designated as free sites. Recent studies indicate a similar relationship exists between the rate of carbon gasification (in CO2 or H2O) and the number of reactive sites as determined by transient kinetics experiments. Utilizing the concept of active or free sites, it was possible to produce a char from Illinois coal having an SO2 adsorption capacity surpassing that of a commercial catalytic activated carbon.

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

1997-01-01

80

The first climatology of stratospheric SO2  

NASA Astrophysics Data System (ADS)

Sulphur dioxide (SO2) is one of the key species determining the aerosol content of the stratosphere. Apart from this study, only three measured profiles of SO2 concentrations (by ATMOS) covering the altitude range of the stratosphere have been published, two of which are heavily perturbed by the Pinatubo eruption and one by El Chichon. Here we present a climatology of monthly and 10° zonal mean profiles of SO2 volume mixing ratios in the altitude range 15-45 km as derived from MIPAS/Envisat measurements from July 2002 until April 2012. The vertical resolution varies from 3.5-4 km in the lower stratosphere up to 6-10 km at the upper end of the profiles with estimated total errors of 5-20 pptv for background conditions of SO2. Comparisons are made with few available observations of SO2 up to high altitudes from ATMOS, for volcanically perturbed situations in the lower stratosphere from ACE-FTS and at the lowest altitudes with stratospheric in-situ observations. The dataset proves for the first time several features of the stratospheric SO2 distribution, which up to now, have only been shown by models: (1) the local maximum of SO2 at around 25-30 km altitude from conversion of COS as the pre-curser of the Junge layer and (2) the downwelling of SO2-rich air to altitudes of 25-30 km at high latitudes during winter and its subsequent depletion during spring as cause for the sudden appearance of enhanced concentrations of condensation nuclei. Comparison with model results of SO2 from the SPARC aerosol assessment report indicate several inconsistencies between simulations and our observations. Further, dedicated EMAC model runs reveal that the strong increase of SO2 to values of 80-100 pptv in the upper stratosphere can only be explained by taking into account visible and near-IR photolysis of H2SO4 and, in addition, a meteoritic sink. Lower stratospheric variability of SO2 can mainly be explained by volcanic activity. A modulation of the mid-stratospheric maximum could be observed for several equatorial eruptions during the time period of observations.

Höpfner, Michael; Brühl, Christoph; Glatthor, Norbert; Grabowski, Udo; Kellmann, Sylvia; Kiefer, Michael; Lelieveld, Jos; Linden, Andrea; Orphal, Johannes; Stiller, Gabriele; Clarmann, Thomas v.

2013-04-01

81

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.

Olszyk, David M.; Tingey, David T.

1985-01-01

82

SO2 abatement, energy conservation, and productivity at copper cliff  

NASA Astrophysics Data System (ADS)

Inco pioneered the use of tonnage oxygen in nonferrous metallurgy when it commissioned the first industrial oxygen flash smelting process for the treatment of copper concentrates in the early 1950s. This was followed by other applications of oxygen such as the enrichment of reverberatory furnace and Peirce-Smith converter blasts; oxy-fuel smelting in reverb furnaces; and, very recently, flash conversion of chalcocite to copper. Inco is currently implementing a sulfur dioxide abatement project designed to reduce SO2 emissions from the smelter by 60 percent (to 265 kt) in 1994. At that time, oxygen consumption at the smelter will reach about 1.7 t O2/t Cu+Ni. Oxygen smelting and converting technology will lead toa substantial decrease in the use of fossil fuels and to the generation afhigh-strength SO2 off-gases suitable for cost-effective fixation in a new acid plant.

Landolt, C. A.; Dutton, A.; Edwards, J. D.; McDonald, R. N.

1992-09-01

83

CO2-SO2 clathrate hydrate formation on early Mars  

NASA Astrophysics Data System (ADS)

It is generally agreed that a dense CO2-dominant atmosphere was necessary in order to keep early Mars warm and wet. However, current models have not been able to produce surface temperature higher than the freezing point of water. Most sulfate minerals discovered on Mars are dated no earlier than the Hesperian, despite likely much stronger volcanic activities and more substantial release of sulfur-bearing gases into Martian atmosphere during the Noachian. Here we show, using a 1-D radiative-convective-photochemical model, that clathrate formation during the Noachian would have buffered the atmospheric CO2 pressure of early Mars at ~2 bar and maintained a global average surface temperature ~230 K. Because clathrates trap SO2 more favorably than CO2, all volcanically outgassed sulfur would have been trapped in Noachian Mars cryosphere, preventing a significant formation of sulfate minerals during the Noachian and inhibiting carbonates from forming at the surface in acidic water resulting from the local melting of the SO2-rich cryosphere. The massive formation of sulfate minerals at the surface of Mars during the Hesperian could be the consequence of a drop of the CO2 pressure below a 2-bar threshold value at the late Noachian-Hesperian transition, which would have released sulfur gases into the atmosphere from both the Noachian sulfur-rich cryosphere and still active Tharsis volcanism. A lower value of the pressure threshold, down to ~0.5 bar, could have been sufficient to maintain middle and high latitude regions below the clathrate formation temperature during the Noachian and to make the trapping of SO2 in clathrates efficient. Our hypothesis could allow to explain the formation of chaotic terrains and outflow channels, and the occurrence of episodic warm episodes facilitated by the release of SO2 to the atmosphere. These episodes could explain the formation of valley networks and the degradation of impact craters, but remain to be confirmed by further modeling.

Chassefiere, E.; Dartois, E.; Herri, J.; Tian, F.; Schmidt, F.; Mousis, O.; Lakhlifi, A.

2013-12-01

84

CO2-SO2 clathrate hydrate formation on early Mars  

NASA Astrophysics Data System (ADS)

It is generally agreed that a dense CO2-dominant atmosphere was necessary in order to keep early Mars warm and wet. However, current models have not been able to produce surface temperature higher than the freezing point of water. Most sulfate minerals discovered on Mars are dated no earlier than the Hesperian, despite likely much stronger volcanic activities and more substantial release of sulfur-bearing gases into martian atmosphere during the Noachian. Here we show, using a 1-D radiative-convective-photochemical model, that clathrate formation during the Noachian would have buffered the atmospheric CO2 pressure of early Mars at ˜2 bar and maintained a global average surface temperature ˜230 K. Because clathrates trap SO2 more favorably than CO2, all volcanically outgassed sulfur would have been trapped in Noachian Mars cryosphere, preventing a significant formation of sulfate minerals during the Noachian and inhibiting carbonates from forming at the surface in acidic water resulting from the local melting of the SO2-rich cryosphere. The massive formation of sulfate minerals at the surface of Mars during the Hesperian could be the consequence of a drop of the CO2 pressure below a 2-bar threshold value at the late Noachian-Hesperian transition, which would have released sulfur gases into the atmosphere from both the Noachian sulfur-rich cryosphere and still active Tharsis volcanism. A lower value of the pressure threshold, down to ˜0.5 bar, could have been sufficient to maintain middle and high latitude regions below the clathrate formation temperature during the Noachian and to make the trapping of SO2 in clathrates efficient. Our hypothesis could allow to explain the formation of chaotic terrains and outflow channels, and the occurrence of episodic warm episodes facilitated by the release of SO2 to the atmosphere. These episodes could explain the formation of valley networks and the degradation of impact craters, but remain to be confirmed by further modeling.

Chassefière, Eric; Dartois, Emmanuel; Herri, Jean-Michel; Tian, Feng; Schmidt, Frédéric; Mousis, Olivier; Lakhlifi, Azzedine

2013-04-01

85

A Comparison of Ultraviolet and Thermal Infrared SO2 Retrievals of a Near-Pure SO2 Plume  

NASA Astrophysics Data System (ADS)

Volcanic plumes are composed of various amounts of silicate ash, ice, SO42-, SO2 and other gases, all of which vary in abundance and have specific transmission signatures within the TIR. Overlaps in their absorption and scattering features, specifically silicate ash, may lead to overestimates of SO2 unless corrected. The 8.6 ? m SO2 algorithm was developed for passive degassing plumes with little to no silicate ash. Prior to an ash-correction, the capabilities of the 8.6 ? m SO2 algorithm for large SO2 plumes need to be established by comparing it to a well documented technique. In this study, we compare near-coincidental data from the UV Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) and TIR MODerate resolution Imaging Spectroradiometer (MODIS) of a near-pure SO2 plume from the Al-Mishraq State sulfur plant fire on 29 June 2003 and provide an ash-free end member for future SO2 ash-correction studies. On 24 June 2003 a fire started at the Al-Mishraq State sulfur plant near Mosul, Iraq and lasted for approximately one month. On 29 June, EP TOMS and MODIS images were acquired at 0752 and 1010 UTC respectively. A previous EP TOMS retrieval estimated the plume contained 102 kt SO2 compared to the 138 kt detected by MODIS based on the 8.6 ? m retrieval. The resampling of the MODIS-based retrieval to the coarser spatial resolution of EP TOMS results in a decrease in the MODIS total mass by 9%. Overall, the agreement between the retrieval techniques on a pixel scale is minimal and ranges between 10% to greater than 90% with no discernable spatial pattern. The low agreement between the two retrievals is likely the result of differences in spatial resolution of the EP TOMS and MODIS measurements, sensitivity of the SO2 estimates to atmospheric absorption and scattering and solar illumination, variations in plume height with distance from the fire and time of data acquisition.

Kearney, C.; Watson, I. M.; Bluth, G. J.; Carn, S.; Realmuto, V. J.

2007-05-01

86

Highly sensitive SnO 2 thin film NO 2 gas sensor operating at low temperature  

Microsoft Academic Search

Thin films of pure nano-crystalline SnO2 and WO3-doped SnO2 in different concentrations (3wt.% and 5wt.%) are deposited using sol–gel spin coating technique on glass substrates. The structural and morphological properties of these films are investigated using XRD, TEM and AFM. The sensitivity and selectivity of these films are tested to different reducing and oxidizing gases such as SO2, NH3, NO2

Jaswinder Kaur; Somnath C. Roy; M. C. Bhatnagar

2007-01-01

87

SOx on ceria from adsorbed SO2  

NASA Astrophysics Data System (ADS)

Results from first-principles calculations present a rather clear picture of the interaction of SO2 with unreduced and partially reduced (111) and (110) surfaces of ceria. The Ce3+/Ce4+ redox couple, together with many oxidation states of S, give rise to a multitude of SOx species, with oxidation states from +III to +VI. SO2 adsorbs either as a molecule or attaches via its S-atom to one or two surface oxygens to form sulfite (SO32-) and sulfate (SO42-) species, forming new S-O bonds but never any S-Ce bonds. Molecular adsorption is found on the (111) surface. SO32- structures are found on both the (111) and (110) surfaces of both stoichiometric and partially reduced ceria. SO42- structures are observed on the (110) surface together with the formation of two reduced Ce3+ surface cations. SO2 can also partially heal the ceria oxygen vacancies by weakening a S-O bond, when significant electron transfer from the surface (Ce4f) into the lowest unoccupied molecular orbital of the SO2 adsorbate takes place and oxidizes the surface Ce3+ cations. Furthermore, we propose a mechanism that could lead to monodentate sulfate formation at the (111) surface.

Lu, Zhansheng; Müller, Carsten; Yang, Zongxian; Hermansson, Kersti; Kullgren, Jolla

2011-05-01

88

High SO2 Removal Efficiency Testing.  

National Technical Information Service (NTIS)

This document provides a discussion of the technical progress on DOE/PETC project number DE-AC22-92PC91338, 'High Efficiency SO2 Removal Testing', for the time period 1 April through 30 June 1997. The project involves testing at six full-scale utility flu...

Gary Blythe

1997-01-01

89

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...

90

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...

91

Selection of SO2 Control for Non-Steady-State Operating Conditions  

NASA Astrophysics Data System (ADS)

Most proven SO2 scrubbing processes are applied under quasi-steady-state conditions. Due to the low solubility of SO2 in water, an alkali is added in the suspended or dissolved state and fed proportionally to the quantity of SO2 entering the scrubber. Highly variable gas composition and flow requires careful monitoring and unusual flexibility of the scrubber system. In addition to SO2, concentration of other gases such as oxygen and carbon dioxide can significantly affect the choice of a process. Selection of scrubbing processes and systems is described for two cases: TBRC™ Copper Smelting and Secondary Lead Smelting effluents.

Daniele, R. A.; Selmeczi, J. G.

1981-03-01

92

Infrared spectroscopy of SO2 aqueous solutions.  

PubMed

The chemistry of SO2 solutions was studied with infrared transmission and total internal reflection (ATR) spectroscopy. The cross-sections of the SO2 stretching vibrations v1, v3 and the combination band of v1 + v3 were obtained and found to be slightly different from their gas phase values. Six features we associate with sulfur-containing ions were observed. We present the first infrared evidence for the bisulfite ion HOSO2- through detection of its OH stretching vibration. Other features may be associated with HSO3-, another isomer of the bisulfite ion, and a new compound we propose to be H2S2O6(2-). We found no evidence for sulfurous acid H2SO3. PMID:12212735

Zhang, Zhenfeng; Ewing, George E

2002-08-01

93

Polar phonons in SO 2 single crystal  

NASA Astrophysics Data System (ADS)

The Raman spectrum of a single SO 2 crystal in various polarization geometries has been measured at 20 K and discussed in terms of LO and TO components of polar crystal modes. Lattice phonons have been assigned on the basis of their behaviour with polarization. Lattice dynamical calculations on both the internal and lattice phonons are in good agreement with experimental data. Using gas-phase transition dipole moments and a dipole—dipole intermolecular potential the angular dispersion of fundamental vibrons has been calculated. For lattice phonons, a combination of atom—atom and electrostatic potential reproduces not only the phonon frequencies but, for polar phonons, also their LO—TO splitting.

Tafi, A.; Procacci, P.; Castellucci, E.; Salvi, P. R.

1991-03-01

94

Io's Non-SO2 Spectral Features  

NASA Astrophysics Data System (ADS)

Introduction: Several absorptions have been identified in the Galileo NIMS spectra of Io that are not related to SO_2. [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. The 3.15? feature: The 3.15? feature is a very weak band having an apparent band depth of less than 4% of the continuum - in contrast to many of the SO_2 features, which have apparent band depths ranging from 15-70%. The 3.15? feature is reasonably ubiquitous on the surface of Io so it was seen in global average spectra obtained early in the Galileo mission [2]. The feature has not been identified but has been attributed variously to H_2S, H_2O, or OH stretch [2,3]. A map of this feature shows a variety of correlations. The feature is strongly present at lower latitudes, which suggests that it may be associated with a material less volatile than SO_2. However the absorption does appear above 30 degrees (north and south), suggesting its presence in not strictly a thermal issue. It is interesting that the absorption moves north of the equator above Pele apparently avoiding Pele's large plume deposit, is not present at Culann, yet covers Prometheus completely. The distribution at Prometheus suggests that the material leading to the 3.15? absorption may be associated with the Prometheus SO_2 reservoir - but it is difficult to reconcile that with the behavior of the absorption about Pele and Culann. There is a reasonably good correlation with visibly white material, but the absorption is also present where the white material is absent. Conclusion: The 3.15 micron absorption appears to be associated with the equatorial region and with white surface features, though there are exceptions in both cases. The absorption, which is not present at Pele or Culann and appears to cover Prometheus, is probably not a direct result of plume activity. Acknowledgement: This work was performed at NASA's JPL under a grant from NASA's Planetary Geology and Geophysics program. References: [1] Shirley J. H. (2001) BAAS 33, #3, p1063 [2], Carlson R W et al (1997) GRL 24, p2479-2482, [3]Salama, F. et al., (1990) Icarus 83 p66-82.

Smythe, W. D.; Soderblom, L. A.; Nelson, R. M.

2003-04-01

95

High SO2 Removal Efficiency Testing  

SciTech Connect

This document provides a discussion of the technical progress on DOE/PETC project number DE-AC22-92PC91338, "High Efficiency SO2 Removal Testing", for the time period 1 January through 31 March 1997. The project involves testing at six full-scale utility flue gas desulfurization (FGD) systems, to evaluate low capital cost upgrades that may allow these systems to achieve up to 98% SO2 removal efficiency. The upgrades being evaluated mostly involve using performance additives in the FGD systems. The "base" project involved testing at the Tampa Electric Company?s Big Bend Station. All five potential options to the base program have been exercised by DOE, involving testing at Hoosier Energy?s Merom Station (Option I), Southwestern Electric Power Company?s Pirkey Station (Option II), PSI Energy?s Gibson Station (Option III), Duquesne Light?s Elrama Station (Option IV), and New York State Electric and Gas Corporation?s (NYSEG) Kintigh Station (Option V). The originally planned testing has been completed for all six sites. However, additional testing is planned at the Big Bend Station. The remainder of this document is divided into four sections. Section 2, Project Summary, provides a brief overview of the status of technical efforts on this project. Section 3, Results, summarizes the outcome from technical efforts during the quarter, or results from prior quarters that have not been previously reported. In Section 4, Plans for the Next Reporting Period, an overview is provided of the technical efforts that are anticipated for the second quarter of calendar year 1997. Section 5 contains a brief acknowledgement.

Gary Blythe

1997-04-23

96

High SO2 Removal Efficiency Testing  

SciTech Connect

This document provides a discussion of the technical progress on DOE/PETC project number DE-AC22-92PC91338, "High Efficiency SO2 Removal Testing", for the time period 1 April through 30 June 1997. The project involves testing at six full-scale utility flue gas desulfurization (FGD) systems to evaluate low capital cost upgrades that may allow these systems to achieve up to 98% SO2 removal efficiency. The upgrades being evaluated mostly involve using performance additives in the FGD systems. The "base" project involved testing at the Tampa Electric Company?s Big Bend Station. All five potential options to the base program have been exercised by DOE, involving testing at Hoosier Energy?s Merom Station (Option I), Southwestern Electric Power Company?s Pirkey Station (Option II), PSI Energy?s Gibson Station (Option III), Duquesne Light?s Elrama Station (Option IV), and New York State Electric and Gas Corporation?s Kintigh Station (Option V). The originally planned testing has been completed for all six sites. However, additional testing is being conducted at the Big Bend Station. The remainder of this document is divided into four sections. Section 2, Project Summary, provides a brief overview of the status of technical efforts on this project. Section 3, Results, summarizes the outcome from technical efforts during the quarter, or results from prior quarters that have not been previously reported. In Section 4, Plans for the Next Reporting Period, an overview is provided of the technical efforts that are anticipated for the third quarter of calendar year 1997. Section 5 contains a brief acknowledgment.

Gary Blythe

1997-07-29

97

Carbon-enriched coal fly ash as a precursor of activated carbons for SO 2 removal  

Microsoft Academic Search

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO2 removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900°C in order to develop porosity onto the samples. The performance of these samples in the SO2

M. T. Izquierdo; B. Rubio

2008-01-01

98

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...

99

Simultaneous measurements of atmospheric trace gases and atmospheric visibility by DOAS system  

Microsoft Academic Search

A Long Path Differential Optical Absorption Spectrometer (LP-DOAS) system has been developed to measure simultaneously atmospheric trace gases concentration and spectral extinction coefficient in the visible region over a few hundred meter. Concentrations of atmospheric gases; SO2, NO2, and O3 are evaluated from the differential optical absorption spectra measured by system. Performance of the system was tested in the field

Jeong S. Lee; Young J. Kim

2003-01-01

100

Electron attachment to sulfur oxyhalides: SOF2, SOCl2, SO2F2, SO2Cl2, and SO2FCl attachment rate coefficients, 300-900 K  

Microsoft Academic Search

Electron attachment to SOF2, SOCl2, SO2F2, SO2FCl, and SO2Cl2 was studied with two flowing-afterglow Langmuir-probe apparatuses over the temperature range 300-900 K. Attachment rate coefficients at 300 K are ka=2.6+\\/-0.8×10-10(SOF2), 1.8+\\/-0.5×10-8(SOCl2), 4.8+\\/-0.7×10-10(SO2F2), 2.4+\\/-0.7×10-9(SO2Cl2), and 2.0+\\/-0.6×10-7 cm3 s-1(SO2FCl). Arrhenius plots of the data imply activation energies of 56+\\/-22 meV(SOF2), 92+\\/-40(SO2F2), 44+\\/-22 meV(SOCl2), and 29+\\/-15 meV(SO2Cl2). The rate coefficients for SO2FCl decrease

Thomas M. Miller; Jeffrey F. Friedman; Connor M. Caples; Nicholas S. Shuman; Jane M. van Doren; Michael F. Bardaro; Pho Nguyen; Cindy Zweiben; Matthew J. Campbell; A. A. Viggiano

2010-01-01

101

Cyclic Pb(SO2), Pb(SO2)2 and Pb2(SO2) molecules: Matrix infrared spectra and DFT calculations  

NASA Astrophysics Data System (ADS)

Reactions of laser-ablated lead atoms with SO2 in excess argon produced three new molecules, cyclic Pb(SO2), Pb2(SO2) and Pb(SO2)2, all with ?2-O,O bonded structure, which were identified by 34SO2 and S18O2 isotopic substitutions. The observed infrared spectra and molecular structures of three molecules were confirmed by density functional theoretical calculations. Mulliken and natural charge distributions indicate significant electron transfer from d orbitals of lead metal to SO2 ligand and lead-oxygen bond exhibits strong polarized covalent character.

Tong, Lijie; Wang, Qiang; Liu, Xing; Wang, Xuefeng

2013-06-01

102

Development of combustion data to utilize low-Btu gases as industrial process fuels. Project 8985 special report No. 2, Kiln Burner. [From natural gas to low Btu gas  

Microsoft Academic Search

Data were gathered to determine the performance of a kiln burner when retrofit with three low-Btu gases. The burner was fired on the IGT pilot-scale test furnaces with a load simulating the calcining and reaction zones of a cement kiln. The low- and medium-Btu gases simulated for these combustion trials were Koppers-Totzek oxygen, Wellman-Galusha air, and Winkler air fuel gases.

R. T. Waibel; E. S. Fleming

1978-01-01

103

Electron attachment to sulfur oxyhalides: SOF2, SOCl2, SO2F2, SO2Cl2, and SO2FCl attachment rate coefficients, 300-900 K.  

PubMed

Electron attachment to SOF(2), SOCl(2), SO(2)F(2), SO(2)FCl, and SO(2)Cl(2) was studied with two flowing-afterglow Langmuir-probe apparatuses over the temperature range 300-900 K. Attachment rate coefficients at 300 K are k(a) = 2.6+/-0.8x10(-10)(SOF(2)), 1.8+/-0.5x10(-8)(SOCl(2)), 4.8+/-0.7x10(-10)(SO(2)F(2)), 2.4+/-0.7x10(-9)(SO(2)Cl(2)), and 2.0+/-0.6x10(-7) cm(3) s(-1)(SO(2)FCl). Arrhenius plots of the data imply activation energies of 56+/-22 meV(SOF(2)), 92+/-40(SO(2)F(2)), 44+/-22 meV(SOCl(2)), and 29+/-15 meV(SO(2)Cl(2)). The rate coefficients for SO(2)FCl decrease slightly with temperature, commensurate with the decrease in the capture rate coefficient. Electron attachment to SOF(2) and SO(2)F(2) is nondissociative, while reaction with SOCl(2), SO(2)FCl, and SO(2)Cl(2) is dissociative. Dissociative attachment is dominated by channels arising from S-Cl bond cleavage but also includes a minor channel forming a dihalide product ion. Branching fraction data are reported for the dissociative attachment channels. PMID:20528017

Miller, Thomas M; Friedman, Jeffrey F; Caples, Connor M; Shuman, Nicholas S; Van Doren, Jane M; Bardaro, Michael F; Nguyen, Pho; Zweiben, Cindy; Campbell, Matthew J; Viggiano, A A

2010-06-01

104

A Fabry-Perot interferometer based camera for two-dimensional mapping of SO2 distributions  

NASA Astrophysics Data System (ADS)

We examine a new imaging method for the remote sensing of volcanic gases, which relies on the regularly spaced narrow-band absorption structures in the UV-VIS of many molecules. A Fabry-Perot interferometer (FPI) is used to compare the scattered sunlight radiance at wavelengths corresponding to absorption bands with the radiance at wavelengths in between the bands, thereby identifying and quantifying the gas. In this first theoretical study, we present sample calculations for the detection of sulfur dioxide (SO2). Optimum values for the FPI set-up parameters are proposed. Further, the performance of the FPI method is compared to SO2 cameras. We show that camera systems using a FPI are far less influenced by changes in atmospheric radiative transfer (e.g. due to aerosol) and have a great potential as a future technique to examine emissions of SO2 (or other gases) from volcanic sources and other point sources.

Kuhn, J.; Bobrowski, N.; Lübcke, P.; Vogel, L.; Platt, U.

2014-05-01

105

SO2-induced stability of Ag-alumina catalysts in the SCR of NO with methane  

SciTech Connect

We report on a stabilization effect on the structure and activity of Ag/Al2O3 for the selective catalytic reduction (SCR) of NOx with CH4 imparted by the presence of SO2 in the exhaust gasmixture. The reaction is carried out at temperature above 600 8C to keep the surface partially free of sulfates. In SO2-free gases, catalyst deactivation is fast and measurable at these temperatures. Time-resolved TEM analyses of used samples have determined that deactivation is due to sintering of silver from well-dispersed clusters to nanoparticles to micrometer-size particles with time-on-stream at 625 8C. However, sintering of silver was dramatically suppressed by the presence of SO2 in the reaction gas mixture. The structural stabilization by SO2 was accompanied by stable catalyst activity for the NO reduction to N2. The direct oxidation of methane was suppressed, thus the methane selectivity was improved in SO2-laden gas mixtures. In tests with high-content silver alumina with some of the silver present in metallic form, an increase in the SCR activity was found in SO2-containing gas mixtures. This is attributed to redispersion of the silver particles by SO2, an unexpected finding. The catalyst performance was reversible over many cycles of operation at 625 8C with the SO2 switched on and off in the gas mixture.

She, Xiaoyan; Flytzani-Stephanopoulos, Maria; Wang, Chong M.; Wang, Yong; Peden, Charles HF

2009-04-29

106

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

107

SO2-Rich Equatorial Basins and Epeirogeny of Io.  

National Technical Information Service (NTIS)

Comparison of Io's large scale topography with an SO2 abundance map shows that SO2 is concentrated in equatorial topographic basins. In these basins, about 30 pct. of the surface is covered by SO2 at all elevations above the mean triaxial figure, and SO2 ...

A. S. Mcewen

1991-01-01

108

SO2-rock interaction on Io 2. Interaction with pure SO2  

NASA Astrophysics Data System (ADS)

A Na-S mineral on the surface of Io is required to be the source of the famous atomic cloud. SO2 is a confirmed atmospheric and surface constituent, and because of the rapid volcanic resurfacing rate, the SO2 is buried within the crust, where at least occasionally, over many cycles of burial and eruption, it must contact silicate materials at midlevel crustal temperatures. Surface interaction experiments were performed for a wide variety of silicate compositions showing that interaction products of these with SO2 could be observed at 1123 K on laboratory timescales, even in the absence of external redox agents. Not all experiments produced deposits that could be studied by scanning electron microscopy; some required the greater sensitivity of photoelectron spectroscopy (XPS). Characterization of the alteration products by XPS showed that both oxidized and reduced sulfur species were formed, indicating that a disproportionation mechanism producing a sulfate and a reduced S species although smaller amounts of interaction leading to Na2SO3 formation cannot be ruled out. The reduced sulfur species is best explained as elemental S which was independently documented for two compositions. Scanning electron microscopy studies for those compositions where reaction was extensive enough to be observed showed (1) Na2SO4 for a soda-lime composition, (2) a mixed Na-Ca-sulfate liquid and CaSO4 for AbAnDi and a chondrule glass composition, and (3) Fe-sulfate for a natural obsidian. Infrared spectroscopy for the soda-lime glass composition showed peaks best explained by Na2SO4. We conclude that SO2 disproportionation as well as direct formation from SO3 under oxidizing conditions can produce Na2SO4 by interaction of SO2 with silicates on Io, but Ca and Fe sulfates may form preferentially in more basaltic compositions. As highly oxidizing conditions may be unlikely for Io, the disproportionation mechanism may be more competitive on Io than it is in laboratory experiments. Very low rates of Na2SO4 production are required to supply the Io atomic cloud, so the interaction processes can be very inefficient.

Burnett, D. S.; Goreva, Julia; Epstein, S.; Haldemann, Susan L.; Johnson, Mary L.; Rice, Alan

1997-08-01

109

Intercomparison of NO x , SO2, O3, and aromatic hydrocarbons measured by a commercial DOAS system and traditional point monitoring techniques  

NASA Astrophysics Data System (ADS)

A field-based intercomparison study of a commercial Differential Optical Absorption Spectroscopy (DOAS) instrument (OPSIS AB, Sweden) and different point-sample monitoring techniques (PM, based on an air monitoring station, an air monitoring vehicle, and various chemical methods) was conducted in Beijing from October 1999 to January 2000. The mixing ratios of six trace gases including NO, NO2, SO2, O3, benzene, and toluene were monitored continuously during the four months. A good agreement between the DOAS and PM data was found for NO2 and SO2. However, the concentrations of benzene, toluene, and NO obtained by DOAS were significantly lower than those measured by the point monitors. The ozone levels monitored by the DOAS were generally higher than those measured by point monitors. These results may be attributed to a strong vertical gradient of the NO-O3-NO2 system and of the aromatics at the measurement site. Since the exact data evaluation algorithm is not revealed by the manufacturer of the DOAS system, the error in the DOAS analysis can also not be excluded.

Xie, Pinhua; Liu, Wenqing; Fu, Qiang; Wang, Ruibin; Liu, Jianguo; Wei, Qingnong

2004-04-01

110

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

111

Chinese SO2 pollution over Europe - Part 2: Simulation of aerosol and cloud condensation nuclei formation  

NASA Astrophysics Data System (ADS)

We report on sulfur dioxide (SO2) induced formation of aerosols and cloud condensation nuclei in an SO2 rich aged (9 days) pollution plume of Chinese origin, which we have detected at 5-7 km altitude during a research aircraft mission over the East Atlantic off the West coast of Ireland. Building on our measurements of SO2 and other trace gases along with plume trajectory simulations, we have performed model simulations of SO2 induced formation of gaseous sulfuric acid (GSA, H2SO4) followed by GSA induced formation and growth of aerosol particles. We find that efficient photochemical SO2 conversion to GSA took place in the plume followed by efficient formation and growth of H2SO4-H2O aerosol particles. Most particles reached sufficiently large sizes to act as cloud condensation nuclei whenever water vapor supersaturation exceeded 0.1-0.2%. As a consequence, smaller but more numerous cloud droplets are formed, which tend to increase the cloud albedo and to decrease the rainout efficiency. The detected plume represents an interesting example of the environmental impact of long range transport of fossil fuel combustion generated SO2.

Fiedler, V.; Arnold, F.; Schlager, H.; Pirjola, L.

2009-01-01

112

Carbon-enriched coal fly ash as a precursor of activated carbons for SO2 removal.  

PubMed

Carbon-enriched coal fly ash was evaluated in this work as a low-cost adsorbent for SO2 removal from stack gases. The unburned carbon in coal fly ash was concentrated by mechanical sieving and vegetal oil agglomeration. The carbon concentrates were activated with steam at 900 degrees C in order to develop porosity onto the samples. The performance of these samples in the SO2 abatement was tested in the following conditions: 100 degrees C, 1000 ppmv SO2, 5% O2, 6% water vapor. A good SO2 removal capacity was shown by some of the studied samples that can be related to their textural properties. Cycles of SO2 adsorption/regeneration were carried out in order to evaluate the possibility of thermal regeneration and re-use of these carbons. Regeneration of the exhausted carbons was carried out at 400 degrees C of temperature and a flow of 25 ml/min of Ar. After each cycle, the SO2 removal capacity of the sample decreases. PMID:18155355

Izquierdo, M T; Rubio, B

2008-06-30

113

Radiative forcing of SO2 and NOx: A case study in Beijing  

NASA Astrophysics Data System (ADS)

A case study was performed in Beijing in 2000 to observe concentrations Of SO2 and NO, in the atmosphere and to evaluate their radiative impact. It was found that the concentrations of these gases are usually high in the morning due to a temperature inversion in the boundary layer. The average concentrations obtained from the observations are much higher than those used in the McClatchey reference atmosphere. The radiative impacts of these gases are calculated using a line-by-line radiative transfer model. The results show that the radiative forcing at the surface due to SO2 is 0.0576 W m(-2) and that due to NOx is 0.0032 W m(-2). These figures are almost compatible with that due to CFC11.

Sun, Z. A.; Wang, X. Y.; Zeng, X. N.

2006-03-01

114

Simultaneous Control of Hg, SO2, and NOx by Novel Oxidized Calcium-Based Sorbents  

Microsoft Academic Search

Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents leads to a significant improvement in elemental Hg vapor (Hg), SO2, and NOx removal from simulated flue gases. In the study presented here, two classes of Ca-based sorbents (hydrated limes and silicate compounds) were investigated. A number of oxidizing additives at different

S. Behrooz Ghorishi; Carl F. Singer; Wojciech S. Jozewicz; Charles B. Sedman; Ravi K. Srivastava

2002-01-01

115

A re-evaluation of the 1991 Pinatubo SO{2} emission using TOMS  

NASA Astrophysics Data System (ADS)

Explosive volcanic eruptions influence the atmosphere and environment from days to years depending on the amount of sulfur species and ash erupted. Large volcanic eruptions, such as Pinatubo, have much stronger effects on the atmospheric chemistry and global climate change since huge amounts of SO{2} are directly erupted into the stratosphere. The June 1991 Pinatubo eruption is the largest eruption of the satellite era, and accurate retrievals of emitted sulfur and ash species are therefore crucial in understanding its atmospheric impacts. The Total Ozone Mapping Spectrometer (TOMS) is routinely used to map and quantify SO{2} for volcanic eruptions. Column amounts of SO{2} and aerosol indices (AI, which represents the ash and aerosol amount qualitatively) for each pixel can be retrieved and then a total mass of SO{2} within the volcanic cloud can be calculated. The SO{2} cloud from the Pinatubo eruption has been studied by Bluth et al. (GRL, Vol. 19, No. 2, 1992). Uncertainties from missing data, saturation, gaps and overlap between neighboring pixels may bring errors in the estimation of initially erupted SO{2} amounts and SO{2} removal rate. An iterative SO{2} algorithm, which was developed by scientists from NASA, is used for getting a more accurate result of total column SO{2} in each pixel. The gap and overlap problem of neighboring pixels is addressed by resampling the data into grids using a nearest neighbor method. Missing data problems in the TOMS datasets due to periodic transmission interruptions are treated by a variety of interpolation models. We have been analyzing the accuracy of a variety of reconstruction methods. The goals of this project include revised tonnage values for daily cloud images; this information will be used to derive a more accurate emitted sulfur dioxide mass and removal rate. Studies of gas and particle separation in the TOMS UV dataset will be supplemented by and compared to IR data analyses.

Guo, S.; Bluth, G. J.; Watson, I. M.; Rose, W. I.

2001-12-01

116

Simultaneous Removal of SO2\\/NOx by Corona Disharge Plasma  

Microsoft Academic Search

An improved wire-to-plate type plasma reactor was devised to reduce NOx\\/SO2 in simulated flue gas. Nozzle type electrodes were installed in the front of wire electrodes for injecting and activating deNOx\\/deSO2 additives. Experimental results indicate that nozzle type electrodes could effectively activate propene (C3H6) and ammonia (NH3) to produce active radicals, therefore advance NOx\\/SO2 removal. Compared with the NOx removal

Kefeng Shang; Yueran Zhuo; Yan Wu

2009-01-01

117

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

118

7-year temporal trend of anthropogenic SO2 emissions over China identified from GOME observations  

NASA Astrophysics Data System (ADS)

Fossil fuels such as coal and oil contain significant amounts of sulfur When burned this sulfur is generally converted to SO2 The GOME observations showed enhancements of SO2 column amounts due to anthropogenic emission sources These enhancements are identified from the regions with extensive burning of coal smelting of metal ores and heavy industrial activities such as from China Eastern USA the Arabian Peninsula Eastern Europe South Africa and particularly Norilsk Russia Also a comparison with GOME observations of anthropogenic NO2 column amounts is presented In this paper we present time series of SO2 SCDs over China We analyzed GOME data for the time period 1996-2002 Time series over the highly industrialized regions Beijing and Shanghai showed a slight increase in the SO2 SCD attributable to the increased use of coal for power generation in China Zhou 2001 Especially during the GOME-period 1996-2001 coal consumption and SO2 time series reflect similar behaviour However Richter et al 2005 calculated a significant increase in the NO2 concentrations over the industrial areas of China for the time period of 1996-2004 Additionally preliminary results of atmospheric SO2 from SCIAMACHY on board EnviSAT-1 since March 2002 instrument with broader spectral and better spatial resolution is presented The better spatial resolution will help to study and localize the impacts of SO2 emissions on a finer spatial scale References Richter A J P Burrows H Nuess C Granier and U Niemeier Increase in tropospheric nitrogen

Khokhar, M. F.; Beirle, S.; Platt, U.; Wagner, T.

119

Effect of Acid Gases on the Pigment Composition of the Leaves of Trees and Lawn Plants (Vliyanie Kislykh Gazov na Pigmentnyi Sostav Listev Drevesnykh i Gazonykh Rastenii).  

National Technical Information Service (NTIS)

The chlorophyll a and b, carotene, lutein, violaxanthin, and neoxanthin contents in the leaves of plants, subjected during various phases of their growth and development to acid gases such as SO2, NO2, F, HF, and P2O5 in various concentrations, were studi...

V. V. Suslova V. S. Nikoloevskii

1971-01-01

120

A Balloon Sounding Technique for Measuring SO2 Plumes  

NASA Technical Reports Server (NTRS)

This paper reports on the development of a new technique for inexpensive measurements of SO2 profiles using a modified dual-ozonesonde instrument payload. The presence of SO2 interferes with the standard electrochemical cell (ECC) ozonesonde measurement, resulting in -1 molecule of O3 reported for each molecule of SO2 present (provided [O3] > [SO2]). In laboratory tests, an SO2 filter made with Cr03 placed on the inlet side of the sonde removes nearly 100% of the SO2 present for concentrations up to 60 ppbv and remained effective after exposure to 2.8 X 10(exp 16) molecules of SO2 [equivalent to a column approximately 150 DU (1 DU = 2.69 X 10(exp 20) molecules m(exp -2))]. Flying two ECC instruments on the same payload with one filtered and the other unfiltered yields SO2 profiles, inferred by subtraction. Laboratory tests and field experience suggest an SO2 detection limit of approximately 3 pbb with profiles valid from the surface to the ozonopause [i.e., approximately (8-10 km)]. Two example profiles demonstrate the success of this technique for both volcanic and industrial plumes.

Morris, Gary A.; Komhyr, Walter D.; Hirokawa, Jun; Lefer, Barry; Krotkov, Nicholay; Ngan, Fong

2010-01-01

121

The microwave absorption of SO2 in the Venus atmosphere  

NASA Astrophysics Data System (ADS)

Sulfur dioxide has a strong and complex rotational spectrum in the microwave and far infrared regions. The microwave absorption due to SO2 in a CO2 mixture is calculated for conditions applicable to the Venus atmosphere. It is shown that at the concentrations detected by Pioneer-Venus in situ measurements, SO2 may be expected to contribute significantly to the microwave opacity of the Venus atmosphere. In particular, SO2 might provide the major source of opacity in the atmospheric region immediately below the main sulfuric acid cloud deck. The spectrum is largely nonresonant at the pressures where SO2 is expected to occur, however.

Janssen, M. A.; Poynter, R. L.

1981-04-01

122

Regional climatic effects of atmospheric SO2 on Mars  

NASA Astrophysics Data System (ADS)

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.

123

Inspection of non-CO 2 greenhouse gases from emission sources and in ambient air by Fourier-transform-infrared-spectrometry: Measurements with FTIS-MAPS  

Microsoft Academic Search

Infrared spectrometry is a versatile basis to analyse greenhouse gases in the atmosphere. A multicomponent air pollution software (MAPS) was developed for retrieval of gas concentrations from radiation emission as well as absorption measurements. Concentrations of CO, CH4, N2O, and H2O as well as CO2, NO, NO2, NH3, SO2, HCl, HCHO, and the temperature of warm gases are determined on-line.

Klaus Schäfer; Rainer Haus; Jörg Heland

1994-01-01

124

SO2 and NO(X) conversion rates in the Kuwait oil fire smoke plume  

SciTech Connect

Aircraft measurements of the Kuwait oil fire smoke plumes during August 1991 are examined to estimate the conversion rates SO2 and NO(X) (NO+NO2) to sulfate and nitrate, respectively. A method based on evaluating a Lagrangian mass conservation equation for the ratios of SO2 and NO(X) to CO2 is used to estimate plume dilution and conversion rates. The loss process is expressed as first and second order, and NO(X) concentration serves as a surrogate for the oxidizing species in the second-order reaction. Continuous measurements of SO2 and NO(X) within the smoke plume indicate that SO2 and NO(X) conversion rates were approximately 1%/h and 2%/h, 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 NO(X) conversion rates predicted by the box model were less than or equal to 1%/h and 2% to 30%/h, 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 NO(X) calculated from the field data may be the average conversion rate associated with nighttime and early-morning chemistry.

Smyth, S.B.; Peters, L.K.; Berkowitz, C.M.; Daum, P.H.; Rodgers, M.O. [Pacific Northwest Laboratory, Richland, WA (United States)]|[Univ. of Kentucky, Lexington, KY (United States)]|[Brookhaven National Laboratory, Upton, NY (United States)]|[Georgia Inst. of Technology, Atlanta, GA (United States)

1994-08-01

125

Influence of O2 and H2O on carbothermal reduction of SO2 by oil-sand fluid coke.  

PubMed

To develop a new process for removing high-concentration SO2 from industrial flue gases, the carbothermal reduction of SO2 by oil-sand fluid coke at 700 degrees C was investigated by varying the inlet concentration of either O2 or H2O. Concentrations of O2 and H2O ranged from 0 to 20% and from 0 to 30%, respectively, in a stream of SO2 (18%) with the balance helium. Addition of O2 and H2O was found to enhance SO2 reduction. The enhancement was attributed to the reducing gases, CO and H2, produced by solid-gas reactions between carbon and O2 or H2O. The effects of O2 and H2O on sulfur yield, however, were bifacial: adding O2 and/or H2O increased the sulfur yield when SO2 conversion was incomplete, otherwise, it decreased the sulfur yield through the formation of sulfides such as H2S. The results of a thermodynamic analysis were in a good agreementwith the experimental results, suggesting that gas-solid reactions were slow enough to allow gas-phase equilibrium. This study indicates that carbon, such as oil-sand fluid coke, can be utilized to remove SO2 in flue gases containing O2/H2O and to convert it to elemental sulfur. PMID:16475356

Feng, Wenguo; Jia, Charles Q

2005-12-15

126

Reversible capture of SO2 through functionalized ionic liquids.  

PubMed

Emission of SO2 in flue gas from the combustion of fossil fuels leads to severe environmental problems. Exploration of green and efficient methods to capture SO2 is an interesting topic, especially at lower SO2 partial pressures. In this work, ionic liquids (ILs) 1-(2-diethylaminoethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Et2 NEMim][Tf2 N]) and 1-(2-diethylaminoethyl)-3-methylimidazolium tetrazolate ([Et2 NEMim][Tetz]) were synthesized. The performances of the two ILs to capture SO2 were studied under different conditions. It was demonstrated that the ILs were very efficient for SO2 absorption. The [Et2 NEMim][Tetz] IL designed in this work could absorb 0.47 g(SO2)g(IL)(-1) at 0.0101 MPa SO2 partial pressure, which is the highest capacity reported to date under the same conditions. The main reason for the large capacity was that both the cation and the anion could capture SO2 chemically. In addition, the IL could easily be regenerated, and the very high absorption capacity and rapid absorption/desorption rates were not changed over five repeated cycles. PMID:23681974

Yang, Dezhong; Hou, Minqiang; Ning, Hui; Ma, Jun; Kang, Xinchen; Zhang, Jianling; Han, Buxing

2013-07-01

127

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...

128

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...

129

Alkalized-Alumina Attritioning and SO2 Sorption Rates.  

National Technical Information Service (NTIS)

The Bureau of Mines conducted studies related to SO2 air pollution to determine attritioning rates, SO2 sorption rates, and sulfur loads that could be obtained on commercial alkalized alumina sorbent pellets. Fluidized-bed attritioning rates ranged from 0...

J. W. Town P. E. Sanker H. J. Kelly

1969-01-01

130

Low NOx Combustion Systems with SO2 Control Using Limestone.  

National Technical Information Service (NTIS)

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 pulveri...

D. C. Drehmel G. B. Martin J. O. Milliken J. H. Abbott

1985-01-01

131

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...

132

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

133

New electrolytes for Li/SO 2 cells  

NASA Astrophysics Data System (ADS)

Aromatic and aliphatic sulfones and, more particularly, dimethyl sulfone (DMSO 2), used as cosolvents with sulfur dioxide allow the dissolution of various lithium salts. The dependence of the conductivity on the concentration of both lithium salts and DMSO 2 has been studied. Lithium bromide and LiCl based electrolytes can be obtained with high conductivities, the best being LiBr/DMSO 2/SO 2 (32 × 10 -3 ? -1 cm -1) and LiCl/DMSO 2/SO 2 (21 × 10 -3 ? -1 cm -1). These conductivities are of the same order of magnitude as those for LiBr/AN/SO 2 electrolytes. However, the high solubility of LiCl in liquid SO 2 — via DMSO 2 — may offer a suitable alternative to the electrolytes currently used in Li/SO 2 cells.

Sarradin, J.; Messina, R.; Perichon, J.

134

SO2 flux measurements at Masaya volcano, Nicaragua - apparent downwind depletion due to topography  

NASA Astrophysics Data System (ADS)

For more than three decades, Masaya volcano, Nicaragua has been a choice volcano for ground-based remote sensing of volcanic SO2 and other gases and is an ideal location to investigate behaviour of boundary layer volcanic gas plumes. Recent advances in miniature UV systems have enabled improvement in techniques for determining the speed of volcanic plumes (previously the greatest source of uncertainty in volcanic SO2 fluxes). This has now allowed for more in depth investigations of other important factors affecting remotely measured SO2 flux. Over 700 SO2 measurements at Masaya in 2005 and 2006 revealed that measurements 15 km downwind of the active vent were systematically 30-50% less than those measured only 5 km from the vent. Dry deposition of sulphur from the plume and conversion of SO2 to sulphate aerosols within the plume are not sufficient to account for the apparent loss. The site 15 km downwind is located on a ridge over which local trade winds and the entrained plume accelerate. Given the geometry of the ridge, topographic modification of winds is the most plausible source of the 30-50% apparent loss, as the enhanced wind speeds lead to dilution of the plume along the axis of propagation. Thus, plume speeds must be measured at plume height at the location of the flux measurement in order to accurately determine SO2 fluxes. This also has significant implications for accurate estimates of the volumes of magma degassed and necessitates that earlier data sets be re-evaluated. Clearly, now that plume speeds can be easily and accurately measured, it is crucial that all sources of uncertainty be fully evaluated prior to any SO2 flux survey.

Williams-Jones, G.; Nadeau, P. A.

2007-05-01

135

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

Code of Federal Regulations, 2013 CFR

...the test analyzer does not have an integral strip chart or digital data recorder, connect the analyzer output to a suitable strip chart or digital data recorder. This recorder shall have a chart width of at least 25 centimeters, a...

2013-07-01

136

Measurements of Air Concentrations of SO 2 , NO 2 and NH 3 at Rural and Remote Sites in Asia  

Microsoft Academic Search

Sensitive diffusive samplers for concentration measurements in ambient airhave been used successfully in Sweden for several years. The samplers have theadvantage of being stable at room temperature before, as well as after,sampling, easy to handle, and cost-efficient. Furthermore, they do not requireelectricity or field calibration. In order to test their use in tropical andsubtropical environments and to obtain a preliminary

Martin FERM; HENNING RODHE

1997-01-01

137

Benzene, toluene, ozone, NO 2 and SO 2 measurements in an urban street canyon in Thessaloniki, Greece  

Microsoft Academic Search

Benzene, toluene, sulphur dioxide, ozone and nitrogen dioxide were measured at a mean level of 13.5m above ground in a narrow, four-lane street canyon (height 30m, width 20m) in Thessaloniki, Greece during the period January–July 1997 by means of a commercial differential optical absorption spectrometer (OPSIS DOAS). Primary pollutant levels were found to be 2.5–4.4 times higher during the cold

Kostas A. Kourtidis; Ioannis Ziomas; Christos Zerefos; Evangelos Kosmidis; Panayotis Symeonidis; Epaminondas Christophilopoulos; Stavros Karathanassis; Antonios Mploutsos

2002-01-01

138

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.

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

2012-01-01

139

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

140

Surface Hydrophobicity Causes SO2 Tolerance in Lichens  

PubMed Central

Background and Aims The superhydrophobicity of the thallus surface in one of the most SO2-tolerant lichen species, Lecanora conizaeoides, suggests that surface hydrophobicity could be a general feature of lichen symbioses controlling their tolerance to SO2. The study described here tests this hypothesis. Methods Water droplets of the size of a raindrop were placed on the surface of air-dry thalli in 50 lichen species of known SO2 tolerance and contact angles were measured to quantify hydrophobicity. Key Results The wettability of lichen thalli ranges from strongly hydrophobic to strongly hydrophilic. SO2 tolerance of the studied lichen species increased with increasing hydrophobicity of the thallus surface. Extraction of extracellular lichen secondary metabolites with acetone reduced, but did not abolish the hydrophobicity of lichen thalli. Conclusions Surface hydrophobicity is the main factor controlling SO2 tolerance in lichens. It presumably originally evolved as an adaptation to wet habitats preventing the depression of net photosynthesis due to supersaturation of the thallus with water. Hydrophilicity of lichen thalli is an adaptation to dry or humid, but not directly rain-exposed habitats. The crucial role of surface hydrophobicity in SO2 also explains why many markedly SO2-tolerant species are additionally tolerant to other (chemically unrelated) toxic substances including heavy metals.

Hauck, Markus; Jurgens, Sascha-Rene; Brinkmann, Martin; Herminghaus, Stephan

2008-01-01

141

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

142

Supported polytertiary amines: highly efficient and selective SO2 adsorbents.  

PubMed

Tertiary amine containing poly(propyleneimine) second (G2) and third (G3) generation dendrimers as well as polyethyleneimine (PEI) were developed for the selective removal of SO2. N-Alkylation of primary and secondary amines into tertiary amines was confirmed by FTIR and NMR analysis. Such modified polyamines were impregnated on two nanoporous supports, namely, SBA-15PL silica with platelet morphology and ethanol-extracted pore-expanded MCM-41 (PME) composite. In the presence of 0.1% SO2/N2 at 23 °C, the uptake of modified PEI, G2, and G3 supported on SBA-15PL was 2.07, 2.35, and 1.71 mmol/g, respectively; corresponding to SO2/N ratios of 0.22, 0.4, and 0.3. Under the same conditions, the SO2 adsorption capacity of PME-supported modified PEI and G3 was significantly higher, reaching 4.68 and 4.34 mmol/g, corresponding to SO2/N ratios of 0.41 and 0.82, respectively. The working SO2 adsorption capacity decreased with increasing temperature, reflecting the exothermic nature of the process. The adsorption capacity of these materials was enhanced dramatically in the presence of humidity in the gas mixture. FTIR data before SO2 adsorption and after adsorption and regeneration did not indicate any change in the materials. Nonetheless, the SO2 working capacity decreased in consecutive adsorption/regeneration cycles due to evaporation of impregnated polyamines, rather than actual deactivation. FTIR and (13)C and (15)N CP-MAS NMR of fresh and SO2 adsorbed modified G3 on PME confirmed the formation of a complexation adduct. PMID:24437448

Tailor, Ritesh; Abboud, Mohamed; Sayari, Abdelhamid

2014-02-01

143

Synergistic effects between SO2 and HCOOH on ?-Fe2O3.  

PubMed

Heterogeneous reactions on mineral aerosols remain an important subject in atmospheric chemistry because of their role in altering the properties of particles and the budget of trace gases. Yet, the role of coadsorption of trace gases onto mineral aerosols and potential synergistic effects are largely uncertain, especially synergistic effects between inorganic and organic gas-phase pollutants. In this study, synergistic effects between HCOOH and SO2 were investigated for the first time using in situ diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS). It was found that the heterogeneous reaction of HCOOH is hindered significantly by coexisting SO2. The total amount of formate decreased, whereas the total amount of sulfate was not affected during coadsorption on the surface of ?-Fe2O3. Futhermore, part of the formate on the surface was catalytically decomposed to CO2 by ?-Fe2O3 with the help of SO2. These results suggest a possible mechanism for the observed correlations between sulfate and carboxylate in the atmosphere. PMID:23600701

Wu, Ling-Yan; Tong, Sheng-Rui; Zhou, Li; Wang, Wei-Gang; Ge, Mao-Fa

2013-05-16

144

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

145

Evaluation of Simultaneous SO2/NOx Control Technology.  

National Technical Information Service (NTIS)

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 fr...

K. R. Bruce W. F. Hansen

1993-01-01

146

Collisional Excitation of SO2 in Cold Molecular Clouds  

NASA Astrophysics Data System (ADS)

Using recently calculated collisional rates for SO2 with ortho and para molecular hydrogen, we have calculated the expected emission of the centimeter wavelength lines of SO2 for the physical conditions previling in dark molecular clouds. We have found that the transition connecting the metastable 202 level with the 111 one will be in absorption against the cosmic background for a large range of densities. The 404-313 line is found to be masering for densities below a few 104 cm-3. We have observed the 111-202 transition with the GBT telescope towards some dark clouds. The line is observed, as expected, in absorption and provides an abundance of SO2 in these objects of a few 10-10. The potential use of millimeter lines of SO2 as tracers of the physical conditions of dark clouds is discussed.

Cernicharo, Jose

2012-10-01

147

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

148

Critical flow atomizer in SO 2 spray scrubbing  

Microsoft Academic Search

Owing to its various deleterious effects, abatement of SO2 from point sources assumes significant importance over the years. Spray towers offer great advantages over other gas cleaning devices. The performance of a counter-current spray tower for SO2 scrubbing using water and dilute NaOH deploying an energy efficient critical flow atomizer is reported. The atomizer is capable of generating finer drops

Amitava Bandyopadhyay; Manindra Nath Biswas

2008-01-01

149

Imaging volcanic SO2 plumes with UV cameras  

NASA Astrophysics Data System (ADS)

Ultraviolet (UV) cameras allow the two-dimensional imaging of SO2 distributions at temporal resolutions on the order of 1Hz. Optical bandpass filters that selectively transmit only UV wavelengths at which SO2 absorption occurs (or, for reference, wavelengths at which absorption is negligible) are positioned in the camera's optical system, thus providing selective sensitivity to SO2. As SO2 is one of the main volatile species associated with high-temperature volcanic degassing, UV camera systems are increasingly being applied to volcanic environments for monitoring and research purposes. The relatively high frame rate of these cameras allows the retrieval of SO2 emission fluxes on time scales comparable to those on which other geophysical parameters (e.g. seismicity, deformation) are recorded, thus making an integrated evaluation possible. While impressive imagery of a volcanic plume's extent is readily obtained, lingering challenges include obtaining an accurate SO2 column density calibration, correcting for complex radiative transfer in and around volcanic plumes (which are often visually opaque), and deriving accurate flux measurements truly representative of volcanic activity and not overly biased by atmospheric turbulence and other secondary effects. Here, these issues are addressed, innovative solutions are presented, and example measurements from Kilauea Volcano (Hawaii) are shown. Although time-averaged SO2 emission rates were typically below 10 kg/s (~900 t/d) during measurements in September and October 2011, the high-resolution camera measurements revealed short-period (order of seconds) peaks of more than twice that value. Measurements were taken from different locations between 2 and 7 km distance from the summit vent, thus giving different perspectives of the gas plume. Where possible, links between SO2 emissions and other monitored parameters are identified and interpreted in regard to their connection to physical processes occurring in the volcanic system.

Kern, C.; Werner, C. A.; Doukas, M. P.; Elias, T.; Kelly, P. J.; Sutton, A. J.

2012-04-01

150

The stability of an SO2 atmosphere on Io  

Microsoft Academic Search

Active volcanism observed on Io could provide a continuous source of gases from Io's interior. Only a small fraction of what is coming out of Io's volcanoes is escaping; the bulk of it is being recycled. There must be an atmospheric reservoir which maintains the gases until they have had a chance to recycle. Such an atmosphere must be protected

S. Kumar

1979-01-01

151

SO2-rich equatorial basins and epeirogeny of Io  

NASA Technical Reports Server (NTRS)

Comparison of Io's large scale topography with an SO2 abundance map shows that SO2 is concentrated in equatorial topographic basins. In these basins, about 30 pct. of the surface is covered by SO2 at all elevations above the mean triaxial figure, and SO2 coverage increases with decreasing elevation to as much as 56 pct. at elevations below -1.5 km. The correlation is not good from long 240 to 360 degs where bright areas are covered by red, Pele type plume fallout, and in the polar regions where the topography is poorly known. The histogram of SO2 abundance binned by elevation appears bimodal, with a secondary concentration of SO2 at high elevations, but it is not certain that this is significant. Additional observations suggest that the basins have relatively little higher frequency topographic relief. The distribution of active plumes and hotspots show no obvious correlation with the topography. However, the Pele type plume all erupted from regions higher than the mean figure, and five of the eight Prometheus type plumes are more energetic and are associated with high temperature hotspots, whereas Prometheus type plumes are long lived and require large volatile reservoirs.

Mcewen, Alfred S.

1991-01-01

152

Fractionation of sulfur isotopes during atmospheric processes: SO2 oxidation and photolysis  

NASA Astrophysics Data System (ADS)

Measurements of stable sulfur isotopes can be used to investigate the chemistry of SO2 in the environment. The oxidation pathway of SO2 plays an important role in determining its environmental effect: gaseous oxidation by OH radicals produces gas-phase sulfuric acid that can nucleate to produce new particles and CCN, while heterogeneous oxidation can change the surface properties of existing particles. Stable isotopes have been used in the investigation of these oxidation pathways, but a major limitation is the lack of laboratory studies of the isotopic fractionation factor for the gaseous reaction (Castleman et al., 1974; Leung et al., 2001; Tanaka et al., 1994). An experimental set-up to investigate the kinetic fractionation of 34S/32S (? = k34/k32) during this reaction has been developed. OH radicals are generated by flowing humidified nitrogen past a mercury lamp producing high-energy UV light. SO2 gas with a known isotopic composition reacts with the OH radicals to produce sulfuric acid gas. Collection methods for both H2SO4 and SO2 gases have been characterised. H2SO4 gas is collected in a glass condenser system and washed out with MilliQ water. This collection method introduces no significant isotopic fractionation. SO2 gas is collected in two bubblers containing 6% H2O2 solution at 273 K, which introduces fractionation of 13 ± 2‰ (? = 1.013 ± 0.002) at 273 K, agreeing with aqueous uptake and oxidation (Saltzman et al., 1983). Following collection, BaCl2 is added to precipitate the sulfur as BaSO4 and the solutions are filtered to collect the BaSO4 grains for analysis in the NanoSIMS. Photolytic and aqueous oxidation of SO2 are the main interfering reactions occurring in the system, and were investigated by running the reaction set-up without generating OH radicals. High humidity conditions produce fractionation of 11 ± 7‰ (? = 1.011 ± 0.007) at 293 K, which corresponds well with previous results for the SO2(g)-HSO3-(aq) system (Eriksen, 1972). Comparison with SO2 collection fractionation gives a temperature dependency of 0.1‰/K. At lower humidity the mass-independent signature of the photolytic reaction (Farquhar et al., 2001) is clearly seen, with little interference from the aqueous reaction. After consideration of these interferences, the fractionation during oxidation of SO2 by OH radicals was measured to be 9.8 ± 2.9 ‰ (? = 1.098 ± 0.0029) at 273 K, with a temperature dependency of 0.09 ± 0.12 ‰/K.

Harris, E. J.; Sinha, B.; Hoppe, P.; Crowley, J.; Foley, S. F.

2010-12-01

153

On the absolute calibration of SO2 cameras  

NASA Astrophysics Data System (ADS)

Sulphur dioxide emission rate measurements are an important tool for volcanic monitoring and eruption risk assessment. The SO2 camera technique remotely measures volcanic emissions by analysing the ultraviolet absorption of SO2 in a narrow spectral window between 300 and 320 nm using solar radiation scattered in the atmosphere. The SO2 absorption is selectively detected by mounting band-pass interference filters in front of a two-dimensional, UV-sensitive CCD detector. One important step for correct SO2 emission rate measurements that can be compared with other measurement techniques is a correct calibration. This requires conversion from the measured optical density to the desired SO2 column density (CD). The conversion factor is most commonly determined by inserting quartz cells (cuvettes) with known amounts of SO2 into the light path. Another calibration method uses an additional narrow field-of-view Differential Optical Absorption Spectroscopy system (NFOV-DOAS), which measures the column density simultaneously in a small area of the camera's field-of-view. This procedure combines the very good spatial and temporal resolution of the SO2 camera technique with the more accurate column densities obtainable from DOAS measurements. 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 NFOV-DOAS 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 Popocatépetl, Mexico, between 1 March 2011 and 4 March 2011. Average SO2 emission rates between 4.00 and 14.34 kg s-1 were observed.

Lübcke, P.; Bobrowski, N.; Illing, S.; Kern, C.; Alvarez Nieves, J. M.; Vogel, L.; Zielcke, J.; Delgado Granados, H.; Platt, U.

2013-03-01

154

Simultaneous control of Hg0, SO2, and NOx by novel oxidized calcium-based sorbents.  

PubMed

Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents leads to a significant improvement in elemental Hg vapor (Hg0), SO2, and NOx removal from simulated flue gases. In the study presented here, two classes of Ca-based sorbents (hydrated limes and silicate compounds) were investigated. A number of oxidizing additives at different concentrations were used in the Ca-based sorbent production process. The Hg0, SO2, and NOx capture capacities of these oxidant-enriched sorbents were evaluated and compared to those of a commercially available activated carbon in bench-scale, fixed-bed, and fluid-bed systems. Calcium-based sorbents prepared with two oxidants, designated C and M, exhibited Hg0 sorption capacities (approximately 100 microg/g) comparable to that of the activated carbon; they showed far superior SO2 and NOx sorption capacities. Preliminary cost estimates for the process utilizing these novel sorbents indicate potential for substantial lowering of control costs, as compared with other processes currently used or considered for control of Hg0, SO2, and NOx emissions from coal-fired boilers. The implications of these findings toward development of multipollutant control technologies and planned pilot and field evaluations of more promising multipollutant sorbents are summarily discussed. PMID:11924858

Ghorishi, S Behrooz; Singer, Carl F; Jozewicz, Wojciech S; Sedman, Charles B; Srivastava, Ravi K

2002-03-01

155

Evolution of CO2, SO2, HCl, and HNO3 in the volcanic plumes from Etna  

NASA Astrophysics Data System (ADS)

The volcanic plumes from degassing Etna (Italy) were extensively probed with instruments onboard the Deutsches Zentrum für Luft- und Raumfahrt research aircraft Falcon during the contrail, volcano, and cirrus experiment CONCERT on 29/30 September 2011. Up to 10.4 ppmv SO2and 0.3 ppmv HCl were detected with the atmospheric chemical ionization mass spectrometer AIMS at 3.1 km altitude and 20 km distance to the summit. HNO3 is the dominant reactive nitrogen component in the plumes. Linking aircraft and ground-based observations by Hybrid Single-Particle Lagrangian Integrated Trajectory dispersion modeling, we identify two crater plumes with different compositions primarily injected by the Bocca Nuova and North East craters. Uniquely, we follow their chemical evolution up to 5 h plume age. Our results show that CO2/SO2and SO2/HCl molar ratios are stable in the ageing plumes. Hence, conversion of SO2 to H2SO4 and partitioning of HCl in acidic plume particles play a minor role at dry tropospheric conditions. Thus, these trace gases allow monitoring volcanic activity far from the crater.

Voigt, C.; Jessberger, P.; Jurkat, T.; Kaufmann, S.; Baumann, R.; Schlager, H.; Bobrowski, N.; Giuffrida, G.; Salerno, G.

2014-03-01

156

Model simulations of the competing climatic effects of SO2 and CO2  

NASA Technical Reports Server (NTRS)

Sulfur dioxide-derived cloud condensation nuclei are expected to enhance the planetary albedo, thereby cooling the planet. This effect might counteract the global warming expected from enhanced greenhouse gases. A detailed treatment of the relationship between fossil fuel burning and the SO2 effect on cloud albedo is implemented in a two-dimensional model for assessing the climate impact. Using a conservative approach, results show that the cooling induced by the SO2 emission can presently counteract 50 percent of the CO2 greenhouse warming. Since 1980, a strong warming trend has been predicted by the model: 0.15 C during the 1980-1990 period alone. The model predicts that by the year 2060 the SO2 cooling reduces climate warming by 0.5 C or 25 percent for the Intergovernmental Panel on Climate Change (IPCC) business as usual (BAU) scenario and 0.2 C or 20 percent for scenario D (for a slow pace of fossil fuel burning). The hypothesis is examined that the different responses between the Northern Hemisphere and the Southern Hemisphere can be used to validate the presence of the SO2-induced cooling.

Kaufman, Yoram J.; Chou, Ming-Dah

1993-01-01

157

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

158

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

159

Photochemistry in Terrestrial Exoplanet Atmospheres. II. H2S and SO2 Photochemistry in Anoxic Atmospheres  

NASA Astrophysics Data System (ADS)

Sulfur gases are common components in the volcanic and biological emission on Earth, and are expected to be important input gases for atmospheres on terrestrial exoplanets. We study the atmospheric composition and the spectra of terrestrial exoplanets with sulfur compounds (i.e., H2S and SO2) emitted from their surfaces. We use a comprehensive one-dimensional photochemistry model and radiative transfer model to investigate the sulfur chemistry in atmospheres ranging from reducing to oxidizing. The most important finding is that both H2S and SO2 are chemically short-lived in virtually all types of atmospheres on terrestrial exoplanets, based on models of H2, N2, and CO2 atmospheres. This implies that direct detection of surface sulfur emission is unlikely, as their surface emission rates need to be extremely high (>1000 times Earth's volcanic sulfur emission) for these gases to build up to a detectable level. We also find that sulfur compounds emitted from the surface lead to photochemical formation of elemental sulfur and sulfuric acid in the atmosphere, which would condense to form aerosols if saturated. For terrestrial exoplanets in the habitable zone of Sun-like stars or M stars, Earth-like sulfur emission rates result in optically thick haze composed of elemental sulfur in reducing H2-dominated atmospheres for a wide range of particle diameters (0.1-1 ?m), which is assumed as a free parameter in our simulations. In oxidized atmospheres composed of N2 and CO2, optically thick haze, composed of elemental sulfur aerosols (S8) or sulfuric acid aerosols (H2SO4), will form if the surface sulfur emission is two orders of magnitude more than the volcanic sulfur emission of Earth. Although direct detection of H2S and SO2 by their spectral features is unlikely, their emission might be inferred by observing aerosol-related features in reflected light with future generation space telescopes.

Hu, Renyu; Seager, Sara; Bains, William

2013-05-01

160

On the absolute calibration of SO2 cameras  

NASA Astrophysics Data System (ADS)

Sulphur dioxide emission flux measurements are an important tool for volcanic monitoring and eruption risk assessment. The SO2 camera technique remotely measures volcanic emissions by analysing the ultraviolet absorption of SO2 in a narrow spectral window between 305 nm and 320 nm using solar radiation scattered in the atmosphere. The SO2 absorption is selectively detected by mounting band-pass interference filters in front of a two-dimensional, UV-sensitive CCD detector. While this approach is simple and delivers valuable insights into the two-dimensional SO2 distribution, absolute calibration has proven to be difficult. An accurate calibration of the SO2 camera (i.e., conversion from optical density to SO2 column density, CD) is crucial to obtain correct SO2 CDs and flux measurements that are comparable to other measurement techniques and can be used for volcanological applications. The most common approach for calibrating SO2 camera measurements is based on inserting quartz cells (cuvettes) containing known amounts of SO2 into the light path. It has been found, however, that reflections from the windows of the calibration cell can considerably affect the signal measured by the camera. Another possibility for calibration relies on performing simultaneous measurements in a small area of the camera's field-of-view (FOV) by a narrow-field-of-view Differential Optical Absorption Spectroscopy (NFOV-DOAS) system. This procedure combines the very good spatial and temporal resolution of the SO2 camera technique with the more accurate column densities obtainable from DOAS measurements. 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 NFOV-DOAS system and an Imaging DOAS (IDOAS), 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 IDOAS to verify the calibration curve over the spatial extend of the image. Our results show that calibration cells 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. These effects can lead to an even more significant overestimation or, depending on the measurement conditions, an underestimation of the true CD. Previous investigations found that possible errors can be more than an order of magnitude. However, the spectral information from the DOAS measurements allows to correct for these radiative transfer effects. The measurement presented in this work were taken at Popocatépetl, Mexico, between 1 March 2011 and 4 March 2011. Average SO2 emission rates between 4.00 kg s-1 and 14.34 kg s-1 were observed.

Lübcke, P.; Bobrowski, N.; Illing, S.; Kern, C.; Alvarez Nieves, J. M.; Vogel, L.; Zielcke, J.; Delgado Granados, H.; Platt, U.

2012-09-01

161

Gas-phase SO 2 in absorption towards massive protostars  

NASA Astrophysics Data System (ADS)

We present the first detection of the nu3 ro-vibrational band of gas-phase SO2 in absorption in the mid-infrared spectral region around 7.3?m of a sample of deeply embedded massive protostars. Comparison with model spectra shows that the derived excitation temperatures correlate with previous C2H2 and HCN studies, indicating that the same warm gas component is probed. The SO2 column densities are similar along all lines of sight suggesting that the SO2 formation has saturated, but not destroyed, and the absolute abundances of SO2 are high ( ~ 10-7). Both the high temperature and the high abundance of the detected SO2 are not easily explained by standard hot core chemistry models. Likewise, indicators of shock induced chemistry are lacking. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA.

Keane, J. V.; Boonman, A. M. S.; Tielens, A. G. G. M.; van Dishoeck, E. F.

2001-09-01

162

SO2 noontime peak phenomenon in the North China Plain  

NASA Astrophysics Data System (ADS)

Frequent SO2 noontime peak phenomenon was discovered in a detailed analysis on the SO2 concentrations in the North China Plain (NCP). The possible causes and their contributions are analysed. The impacts of such a phenomenon on the sulphur cycle were studied and the implications of the phenomenon for atmospheric chemistry, cloud physics and climate were discussed. Different from the common SO2 diurnal patterns with high nighttime concentrations, NCP witnessed high frequencies of SO2 noontime peaks, with an occurrence frequency of 50-72% at the four stations. Down-mixing of elevated pollution layers, plume transport processes, mountain-valley-winds and fog/high RH haze events were the possible causes. The contribution of each process varies from each other and from station to station, however, neither of those four processes can be neglected. SO2 peaks occurring during noontime instead of nighttime will lead to a 13-35% increase in sulphur dry deposition, 9-23% increase in gas phase oxidation and 8-33% increase in aqueous phase conversions, which will increase the hygroscopicity and the light scattering of aerosols, thus having important impacts on atmospheric chemistry, cloud physics and climate.

Xu, W. Y.; Zhao, C. S.; Ran, L.; Lin, W. L.; Yan, P.; Xu, X. B.

2014-03-01

163

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

164

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

165

Vertical profiling of SO 2 and SO above Venus' clouds by SPICAV/SOIR solar occultations  

NASA Astrophysics Data System (ADS)

New measurements of sulfur dioxide (SO 2) and monoxide (SO) in the atmosphere of Venus by SPICAV/SOIR instrument onboard Venus Express orbiter provide ample statistics to study the behavior of these gases above Venus' clouds. The instrument (a set of three spectrometers) is capable to sound atmospheric structure above the clouds in several observation modes (nadir, solar and stellar occultations) either in the UV or in the near IR spectral ranges. We present the results from solar occultations in the absorption ranges of SO 2 (190-230 nm, and at 4 ?m) and SO (190-230 nm). The dioxide was detected by the SOIR spectrometer at the altitudes of 65-80 km in the IR and by the SPICAV spectrometer at 85-105 km in the UV. The monoxide's absorption was measured only by SPICAV at 85-105 km. We analyzed 39 sessions of solar occultation, where boresights of both spectrometers are oriented identically, to provide complete vertical profiling of SO 2 of the Venus' mesosphere (65-105 km). Here we report the first firm detection and measurements of two SO 2 layers. In the lower layer SO 2 mixing ratio is within 0.02-0.5 ppmv. The upper layer, also conceivable from microwave measurements by Sandor et al. (Sandor, B.J., Todd Clancy, R., Moriarty-Schieven, G., Mills, F.P. [2010]. Icarus 208, 49-60) is characterized by SO 2 increasing with the altitude from 0.05 to 2 ppmv, and the [SO 2]/[SO] ratio varying from 1 to 5. The presence of the high-altitude SO x species could be explained by H 2SO 4 photodissociation under somewhat warmer temperature conditions in Venus mesosphere. At 90-100 km the content of the sulfur dioxide correlates with temperature increasing from 0.1 ppmv at 165-170 K to 0.5-1 ppmv at 190-192 K. It supports the hypothesis of SO 2 production by the evaporation of H 2SO 4 from droplets and its subsequent photolysis at around 100 km.

Belyaev, Denis A.; Montmessin, Franck; Bertaux, Jean-Loup; Mahieux, Arnaud; Fedorova, Anna A.; Korablev, Oleg I.; Marcq, Emmanuel; Yung, Yuk L.; Zhang, Xi

2012-02-01

166

Io's Asymmetric, Sublimation-Dominated SO2 Atmosphere  

NASA Astrophysics Data System (ADS)

Io's SO2 atmosphere appears to be globally asymmetric, being up to ten times denser on the anti-Jupiter hemisphere. At least on that hemisphere, the atmosphere is probably dominated by sublimation of surface frost rather than direct volcanic supply. Evidence for this picture includes: (i) The concentration of the atmosphere at low latitudes, where frost temperatures are expected to be highest, as previously inferred from Lyman-alpha images of Io (Feldman et al. 2000, GRL 27, 1787); (ii) Our new HST UV long-slit spectra, which show that the anti-Jovian SO2 column density varies smoothly with latitude and/or local time, peaking near the subsolar point, and is not strongly concentrated over the Prometheus plume or other volcanos (Jessup et al. 2003, Icarus, submitted); (iii) The tenfold larger equatorial SO2 column density seen on the anti-Jupiter hemisphere in our new spectra, compared to previous disk-resolved UV spectroscopy of the Jupiter-facing side (McGrath et al. 2000, Icarus 146, 476); (iv) A correlation between longitudinal variations in the strength of 19 ? m SO2 gas absorption lines and the global distribution of optically-thick SO2 frost seen in the near-UV, with both peaking on the anti-Jupiter hemisphere; and (v) a decrease in anti-Jovian 19 ? m line strength between Nov. 2001 and Dec. 2002, quantitatively consistent with the expected reduction in SO2 vapor pressure due to frost cooling as Io and Jupiter approach aphelion.

Spencer, J. R.; Jessup, K. L.; Ballester, G. E.; Lellouch, E.; Lopez-Valverde, M.; Richter, M.

2003-05-01

167

Measuring SO2 ship emissions with an ultraviolet imaging camera  

NASA Astrophysics Data System (ADS)

Over the last few years fast-sampling ultraviolet (UV) imaging cameras have been developed for use in measuring SO2 emissions from industrial sources (e.g. power plants; typical emission rates ~ 1-10 kg s-1) and natural sources (e.g. volcanoes; typical emission rates ~ 10-100 kg s-1). Generally, measurements have been made from sources rich in SO2 with high concentrations and emission rates. In this work, for the first time, a UV camera has been used to measure the much lower concentrations and emission rates of SO2 (typical emission rates ~ 0.01-0.1 kg s-1) in the plumes from moving and stationary ships. Some innovations and trade-offs have been made so that estimates of the emission rates and path concentrations can be retrieved in real time. Field experiments were conducted at Kongsfjord in Ny Ålesund, Svalbard, where SO2 emissions from cruise ships were made, and at the port of Rotterdam, Netherlands, measuring emissions from more than 10 different container and cargo ships. In all cases SO2 path concentrations could be estimated and emission rates determined by measuring ship plume speeds simultaneously using the camera, or by using surface wind speed data from an independent source. Accuracies were compromised in some cases because of the presence of particulates in some ship emissions and the restriction of single-filter UV imagery, a requirement for fast-sampling (> 10 Hz) from a single camera. Despite the ease of use and ability to determine SO2 emission rates from the UV camera system, the limitation in accuracy and precision suggest that the system may only be used under rather ideal circumstances and that currently the technology needs further development to serve as a method to monitor ship emissions for regulatory purposes. A dual-camera system or a single, dual-filter camera is required in order to properly correct for the effects of particulates in ship plumes.

Prata, A. J.

2014-05-01

168

Orbifold family unification in SO(2N) gauge theory  

SciTech Connect

We study the possibility of family unification on the basis of SO(2N) gauge theory on the five-dimensional space-time, M{sup 4}xS{sup 1}/Z{sub 2}. Several SO(10), SU(4)xSU(2){sub L}xSU(2){sub 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.

Kawamura, Yoshiharu; Miura, Takashi [Department of Physics, Shinshu University, Matsumoto, Nagano 390-8621 (Japan)

2010-04-01

169

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

170

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

171

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...

172

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...

173

Probabilistic Evaluation of Advanced SO2\\/NOx Control Technology  

Microsoft Academic Search

A new probabilistic modeling environment is described which allows the explicit and quantitative representation of the uncertainties inherent in new environmental control processes for SO2 and NOx removal. Stochastic analyses provide additional insights into the uncertainties in process performance and cost not possible with conventional deterministic or sensitivity analysis. Applications of the probabilistic modeling framework are illustrated via an analysis

H. C. Frey; E. S. Rubin

1991-01-01

174

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...

175

HEMATOLOGIC AND IMMUNOLOGIC STUDIES OF HUMANS EXPOSED TO SO2  

EPA Science Inventory

Immunologic and hematologic parameters were used to evaluate the effects in humans of a single 2 hour exposure to either clean air or 0.75 ppm SO2. Venous blood Samples were obtained before, immediately after, and 24, 48, and 72 hours following the end of exposure. Parameters stu...

176

Hematologic and Immunologic Studies of Humans Exposed to SO2.  

National Technical Information Service (NTIS)

Immunologic and hematologic parameters were used to evaluate the effects in humans of a single 2 hour exposure to either clean air or 0.75 ppm SO2. Venous blood Samples were obtained before, immediately after, and 24, 48, and 72 hours following the end of...

M. L. Peterson S. Harder D. Elliott V. Milholland G. Orlando

1981-01-01

177

SO2 and NOx Control Technology Research, Development, and Demonstration.  

National Technical Information Service (NTIS)

The paper describes 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 se...

R. D. Stern C. B. Sedman F. T. Princiotta

1989-01-01

178

The role of SO2 in volcanism on Io  

USGS Publications Warehouse

Io and Earth are the only planetary bodies known to be volcanically active; the energetics of the eruptive plumes on Io have important structural implications and are closely linked with the presence of sulphur and SO 2. ?? 1979 Nature Publishing Group.

Smith, B. A.; Shoemaker, E. M.; Kieffer, S. W.; Cook, II, A. F.

1979-01-01

179

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 ...

180

High-throughput technology for novel SO2 oxidation catalysts  

NASA Astrophysics Data System (ADS)

We review the state of the art and explain the need for better SO2 oxidation catalysts for the production of sulfuric acid. A high-throughput technology has been developed for the study of potential catalysts in the oxidation of SO2 to SO3. High-throughput methods are reviewed and the problems encountered with their adaptation to the corrosive conditions of SO2 oxidation are described. We show that while emissivity-corrected infrared thermography (ecIRT) can be used for primary screening, it is prone to errors because of the large variations in the emissivity of the catalyst surface. UV-visible (UV-Vis) spectrometry was selected instead as a reliable analysis method of monitoring the SO2 conversion. Installing plain sugar absorbents at reactor outlets proved valuable for the detection and quantitative removal of SO3 from the product gas before the UV-Vis analysis. We also overview some elements used for prescreening and those remaining after the screening of the first catalyst generations.

Loskyll, Jonas; Stoewe, Klaus; Maier, Wilhelm F.

2011-10-01

181

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...

182

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/...

183

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

PubMed

The Indo-Gangetic plain (IGP) has received extensive attention of the global scientific community due to higher levels of trace gases and aerosols over this region. Satellite retrievals and model simulations show that, in particular, the eastern part IGP is highly polluted. Despite this attention, in situ measurements of trace gases are very limited over this region. This paper presents measurements of SO2, CO, CH4, and C2-C5 NMHCs during March 2012-February 2013 over Kolkata, a megacity in the eastern IGP, with a focus on processes impacting their levels. The mean SO2 and C2H6 concentrations during winter and post-monsoon periods were eight and three times higher compared to pre-monsoon and monsoon. Early morning enhancements in SO2 and several NMHCs during winter connote boundary layer effects. Daytime elevations in SO2 during pre-monsoon and monsoon suggest impacts of photo-oxidation. Inter-species correlations and trajectory analysis evince transport of SO2 from regional combustion sources (e.g., coal burning in power plants, industries) along the east of the Indo-Gangetic plain impacting SO2 levels at the site. However, C2H2 to CO ratio over Kolkata, which are comparable to other urban regions in India, show impacts of local biofuel combustions. Further, high levels of C3H8 and C4H10 evince the dominance of LPG/petrochemicals over the study location. The suite of trace gases measured during this study helps to decipher between impacts of local emissions and influence of transport on their levels. PMID:24737018

Mallik, Chinmay; Ghosh, Dipanjan; Ghosh, Debreka; Sarkar, Ujjaini; Lal, Shyam; Venkataramani, S

2014-07-01

184

Detection and Tracking of Volcanic Ash and SO2 and its Impact to Aviation  

NASA Astrophysics Data System (ADS)

The eruptions of Okmok and Kasatochi Volcanoes in August 2008 produced a combination of volcanic ash and SO2 (sulfur dioxide) that impacted aviation across Alaska and the North Pacific Region. The Anchorage Volcanic Ash Advisory Center (A-VAAC) worked closely with the Alaska Volcano Observatory (AVO) and Federal Aviation Administration (FAA) Air Route Traffic Control Center (ARTCC) to ensure that accurate and timely detection and forecast of the ash plume occurred. Volcanic ash poses a hazard to all forms of transportation, but has been shown to be especially dangerous to aviation. Even a small eruption with limited vertical extent to the ash cloud impacts aviation traffic. A significant eruption where the ash cloud penetrates the jet airways (greater than 20,000 feet) requires major re-routing of air traffic, or even the cancellation of flights to ensure the safety of the airways. The AAWU and the AVO have demonstrated substantial experience successfully tracking volcanic ash clouds during the past 15 years. The AAWU issues special aviation warnings for volcanic ash (Volcanic Ash SIGMETs (Significant Meteorological Information)) to warn aircraft of impending ash hazards. However, an additional potential hazard to aviation associated with volcanic eruptions is being examined. A Sulfur Dioxide (SO2) cloud was identified and tracked across the Aleutians, Gulf of Alaska, and eventually into the Lower 48 states. The size and coverage of the SO2 clouds from the Okmok and Kasatochi eruptions may be unprecedented. There are currently no requirements to advise, or warn for SO2 as a hazard to aviation. However, SO2 has been demonstrated as a marker for potential areas of lower concentration volcanic ash. Dispersion models, such as NOAAs HYSPLIT, that are used to track volcanic ash are currently not tuned to track gases such as SO2. SO2 may not be a direct hazard to aviation per se; However, SO2 mixed with water produces H2SO4 (sulfuric acid), and long term exposure to even low concentrations of sulfuric acid may lead to deterioration of airframe paint and acrylic aircraft windows as well as sulfate deposits in the engines. Airlines typically avoid SO2 clouds because these clouds often contain small amounts of ash as well. Relatively new OMI (Ozone Monitoring Instrument) data from the EOS-Aura satellite provides a much higher resolution depiction of the SO2 cloud; However, a major drawback to this capability is that the OMI sensor is located on a Polar Orbiter satellite (where the frequency of this data is sparse). Forecasters in Alaska typically receive only one pass per day from the OMI due to its orbital path. Additional research is needed to better define thresholds and impacts of volcanic ash and SO2 as it relates to aviation. More importantly this research must be transferred rapidly from the research community into forecast operations.

Osiensky, J.; Hall, T.

2008-12-01

185

Limestone injection reduces SO2 and NO /SUB x/ emissions  

SciTech Connect

The phases of Foster Wheeler's programs are presented by which the company developed a less complex low-NO /SUB x/ burner. Two phases involved assessing the potential of premixing limestone with coal to reduce SO2, and evaluating a new method of in-burner sorbent injection. Upper furnace injection of limestone was also evaluated by Conoco at the DuPont facility. The article reports that emission of SO2 was reduced by approximately 50% at a calcium: sulfur mole ratio of 2.5. However, the boiler had to be operated at 20% below full load to achieve the same level of sulfur capture achieved at maximum load with in-burner injection.

Vatsky, J.; Schindler, E.S.

1985-11-01

186

Adsorption of SO2 on sewage sludge-derived materials.  

PubMed

Sewage sludge-derived materials carbonized at temperatures between 400 and 950 degrees C were used for adsorption of sulfur dioxide from dry and moist air. The materials were characterized using sorption of nitrogen and thermal analysis. The sulfur dioxide capacity was measured according to a laboratory-developed breakthrough test. It was found that the capacity of the adsorbents increases with increasing temperature of carbonization. It is likely that during carbonization at high temperatures such catalytic metals as calcium become active. They play a significant role in the SO2 removal process by neutralization of sulfuric acid formed as a result of oxidation of sulfur dioxide in wet conditions. Besides sulfuric acid, various sulfur-containing salts are formed. It was shown that, after their removal using waterwashing,the SO2 capacitysignificantly decreased. PMID:11506018

Bashkova, S; Bagreev, A; Locke, D C; Bandosz, T J

2001-08-01

187

SO2 quantification using the LINUS UV imaging spectrometer  

NASA Astrophysics Data System (ADS)

The Lineate Imaging Near Ultraviolet Spectrometer (LINUS)1,2 has been used to remotely detect and measure sulfur dioxide (SO2). The sensor was calibrated in the lab, with curves of growth created for the 0.29 - 0.31 ? spectral range of the LINUS sensor. Field observations were made of a coal burning plant in St. John's, Arizona at a range of 537 m. The Salt River Coronado plant stacks were emitting on average about 100 ppm and 200 ppm from the left and right stacks respectively. Analysis of the LINUS data matched those values within twenty percent. Possible uses for this technology include remote verification of industry emissions and detection of unreported SO2 sources.

Porter, Michael A.; Olsen, Richard C.; Harkins, Richard M.; Puetz, Angela M.

2006-06-01

188

Limestone injection reduces SO2 and NO \\/SUB x\\/ emissions  

Microsoft Academic Search

The phases of Foster Wheeler's programs are presented by which the company developed a less complex low-NO \\/SUB x\\/ burner. Two phases involved assessing the potential of premixing limestone with coal to reduce SO2, and evaluating a new method of in-burner sorbent injection. Upper furnace injection of limestone was also evaluated by Conoco at the DuPont facility. The article reports

J. Vatsky; E. S. Schindler

1985-01-01

189

Historical Analysis of SO2 Pollution Control Policies in China  

NASA Astrophysics Data System (ADS)

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 (SO2) 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 SO2 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 SO2 control in China, we found that Chinese SO2 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.

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

2009-03-01

190

Historical Analysis of SO 2 Pollution Control Policies in China  

Microsoft Academic Search

Coal is not only an important energy source in China but also a major source of air pollution. Because of this, China’s national\\u000a sulfur dioxide (SO2) emissions have been the highest in the world for many years, and since the 1990s, the territory of China’s south and southwest\\u000a has become the third largest acid-rain-prone region in the world. In order

Cailing Gao; Huaqiang Yin; Nanshan Ai; Zhengwen Huang

2009-01-01

191

AC impedance study of Li\\/SO2 rechargeable cells  

Microsoft Academic Search

The kinetics of lithium passivation and the development of the impedance of carbon electrodes and LiGaCl4 and LiAlCl4 non-solvate electrolytes in rechargeable Li\\/SO2 cells have been studied using the AC impedance technique. The effects of cycling and depth of discharge (DOD) on impedance parameters and the effects of electrolyte concentration on cell performance and open circuit voltage (OCV) are discussed.

T. J. Lee; G. T. K. Fey

1990-01-01

192

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

193

Monitoring of SO2 emissions from industry by passive DOAS  

NASA Astrophysics Data System (ADS)

Sulfur dioxide is a highly toxic air contaminant that harms human health and damages the environment. It is easily converted to sulfuric acid which is the major component in acid rain and to sulfate particles. Coal-burning power plants are the main sources of SO2 pollution. It is necessary to evaluate the emissions from industry for emission reduction strategies. Passive DOAS method has been successfully applied in volcanic plume and atmosphere monitoring because of its advantage of relative simple system with no light source. Here we report the measurement of SO2 total flux from a chimney in plant area in Hefei city (China) with a compact passive DOAS system. The system consists of a small telescope pointing zenith direction and a fibre-coupled OceanOptics USB2000 spectrometer. In the measurement the system was mounted on a mobile platform moving under the plume approximately perpendicular to the plume transport direction and the spectra of the zenith direction were recorded. By combining the integrated gas concentration over the plume cross section with wind velocity data SO2 flux was estimated.

Li, Ang; Liu, Cheng; Xie, Pinhua; Liu, Jianguo; Qin, Min; Dou, Ke; Fang, Wu; Liu, Wenqing

2005-05-01

194

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

195

Sputtering of SO2 by high energy ions  

NASA Technical Reports Server (NTRS)

Sputtering yields of solid SO2 by high energy ions were measured in order to study the mechanism for sputtering dielectrics with ions in the electronic stopping power region. The incident ions were helium and fluorine with energies ranging from 1.5 MeV to 25 MeV. Yields as high as 7000 SO2 molecules/incident F ion were measured; the 1.5 MeV He-4 beam had a sputtering yield of 50. The data are compared to yield measurements made on UF4 and H2O targets. There is a striking similarity in the yield as a function of the incident F energy for all three targets. The data compare favorably with theoretical yield curves based on a new model for the sputtering which considers the electronic excitations induced in the target by the incident beam. Measurements and calculations of this sort are also useful in understanding processes which occur on the surface of Jupiter's satellite Io, which is covered with SO2 frost and bombarded by energetic ions trapped in the Jovian magnetosphere.

Lepoire, D. J.; Cooper, B. H.; Melcher, C. L.; Tombrello, T. A.

1983-01-01

196

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.

197

HDO and SO2 thermal mapping on Venus. II. The SO2 spatial distribution above and within the clouds  

NASA Astrophysics Data System (ADS)

Sulfur dioxide and water vapor, two key species of Venus photochemistry, are known to exhibit significant spatial and temporal variations above the cloud top. In particular, ground-based thermal imaging spectroscopy at high spectral resolution, achieved on Venus in January 2012, has shown evidence for strong SO2 variations on timescales shorter than a day. We have continued our observing campaign using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility to map sulfur dioxide over the disk of Venus at two different wavelengths, 7 ?m (already used in the previous study) and 19 ?m. The 7 ?m radiation probes the top of the H2SO4 cloud, while the 19 ?m radiation probes a few kilometers below within the cloud. Observations took place on October 4 and 5, 2012. Both HDO and SO2 lines are identified in our 7-?m spectra and SO2 is also easily identified at 19 ?m. The CO2 lines at 7 and 19 ?m are used to infer the thermal structure. An isothermal/inversion layer is present at high latitudes (above 60 N and S) in the polar collars, which was not detected in October 2012. The enhancement of the polar collar in October 2012 is probably due to the fact that the morning terminator is observed, while the January data probed the evening terminator. As observed in our previous run, the HDO map is relatively uniform over the disk of Venus, with a mean mixing ratio of about 1 ppm. In contrast, the SO2 maps at 19 ?m show intensity variations by a factor of about 2 over the disk within the cloud, less patchy than observed at the cloud top at 7 ?m. In addition, the SO2 maps seem to indicate significant temporal changes within an hour. There is evidence for a cutoff in the SO2 vertical distribution above the cloud top, also previously observed by SPICAV/SOIR aboard Venus Express and predicted by photochemical models.

Encrenaz, T.; Greathouse, T. K.; Richter, M. J.; Lacy, J.; Widemann, T.; Bézard, B.; Fouchet, T.; deWitt, C.; Atreya, S. K.

2013-11-01

198

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

199

Greenhouse Gases  

MedlinePLUS

... are greenhouse gases? Many chemical compounds present in Earth's atmosphere behave as 'greenhouse gases'. These are gases ... direct sunlight (relative shortwave energy) to reach the Earth's surface unimpeded. As the shortwave energy (that in ...

200

Manure Gases  

MedlinePLUS

... gases of most concern are ammonia and hydrogen sulfide. Other gases of concern include methane and carbon ... Since most of these gases in particular hydrogen sulfide are heavier-than-air, they tend to settle ...

201

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

202

Laser stark spectroscopy of SO2 with the HCN laser  

NASA Technical Reports Server (NTRS)

The far infrared laser Stark spectrum of SO2 was investigated using the 337-micron line of the HCN laser. Two distinct families, one originating at low field and the other at high field, were observed. The high field transition is identified. A significant fourth-order Stark shift was observed for this transition in the presence of a large second-order Stark shift. The zero-field frequency of the assigned transition was obtained by accounting for the fourth-order contribution.

Sarker, J. C.; Johnston, L. H.; Bhattacharjee, R. L.; Sudhakaran, G. R.

1991-01-01

203

SO2 Emission Control: The Problem and Solutions  

NASA Astrophysics Data System (ADS)

In the past 10 years sulfur oxide emission control has been a key factor in the economic performance of many smelting operations, and markedly effects the choice of process and the design of new installations. This paper presents a review of pyrometallurgical processes for the production of copper, lead, and zinc. To put the problem in perspective, the review first outlines sulfur emission sources and alternate processing techniques, including oxygen enrichment and continuous and flash smelting. Alternate control systems, including sulfuric acid, liquid SO2, elemental sulfur, and weak gas scrubbing processes are then described from operational and economic standpoints.

Friedman, Leonard J.

1981-03-01

204

Oxidation of CO by SO2: a theoretical study.  

PubMed

The elementary reaction SO(2) + CO --> CO(2) + SO((3)Sigma) (1) and the subsequent reaction SO((3)Sigma) + CO --> CO(2) + S((3)P) (2) have been studied by the application of the Gaussian-3//B3LYP quantum chemical approach to characterize the potential energy surfaces and transition state kinetic analysis to derive rate coefficients. Reaction 1 is found to take place via two transition states (TS), a cis-OSOCO TS and a trans-OSOCO TS. Reaction via the cis-TS is concerted and takes place on a singlet surface. Intersystem crossing to the final products occurs after passage through the barrier on the singlet surface. The trans-TS leads to a very weakly bound singlet OSOCO intermediate that then passes through a second TS (on the triplet surface) to form the products. Reaction 2 takes place on triplet surfaces. There is a concerted reaction through a cis-SOCO TS and a weakly bound trans-SOCO has also been identified. Reaction 2 is analogous to the reaction CO + O(2)((3)Sigma) --> CO(2) + O((3)P) (3), and this reaction has been reinvestigated at a similar level of theory and the rate coefficient derived by quantum chemistry is compared with experiment. The sensitive effects of trace impurities such as H(2), H(2)O, and hydrocarbons on the accurate experimental determination of the rate coefficient of reaction 3 is discussed. Using rate coefficients for reactions 1 and 2 obtained via quantum chemical calculations, we have been unable to model the extent of decomposition of SO(2) measured in a shock tube study of reaction between SO(2) and CO [Bauer, S. H.; Jeffers, P.; Lifshitz, A.; Yadava, B. P. Proc. Combust. Inst. 1971, 13, 417]. In light of the known sensitivity of reaction 3 to trace impurities, we have incorporated trace amounts of H(2), CH(4), or H(2)O, together with our rate coefficients for (1) and (2), in a kinetic model of Alzueta et al. [Combust. Flame 2001, 127, 2234], which is then shown to be able to substantially model the SO(2) data of Bauer et al. In the course of this modeling study we also computed heats of formation for a number of sulfur-containing small molecules: HS, HSO, HSOH, HOSO, HS(2), HSO(2), HOSO(2), HOSOH, and HOSHO. PMID:16833537

Bacskay, George B; Mackie, John C

2005-03-10

205

Combined removal of SO2, NOx, and fly ash from simulated flue gas using pulsed streamer corona  

Microsoft Academic Search

A pulse-energized electron reactor utilizing pulsed streamer corona has been developed for the combined removal of SO2, NO x, and particles from effluent gases. In the pulse-energized electron reactor process, fast-rising narrow high voltage pulses are superimposed on a DC bias voltage and applied to a nonuniform electric field geometry to generate pulsed streamer corona. The pulsed streamer corona produces

J. S. Clements; A. Mizuno; W. C. Finney; R. H. Davis

1989-01-01

206

Catching gaseous SO2 in cone-type lanthanide complexes: an unexpected coordination mode for SO2 in f-element chemistry.  

PubMed

Easy come, easy go: the first molecular SO(2) complexes of the lanthanides (Ln=Sm, Eu) have been prepared. The compounds can reversibly coordinate gaseous SO(2). Concomitant with the addition and removal of SO(2), the color of the complexes changes reversibly. The structures of the SO(2) compounds could be confirmed in solution and in the solid state. PMID:22473788

Benndorf, Paul; Schmitt, Sophia; Köppe, Ralf; Oña-Burgos, Pascual; Scheurer, Andreas; Meyer, Karsten; Roesky, Peter W

2012-05-14

207

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.

Izu, Noriya; Hagen, Gunter; Schonauer, Daniela; Roder-Roith, Ulla; Moos, Ralf

2011-01-01

208

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

209

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

210

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

211

Mineral dust photochemistry induces nucleation events in the presence of SO2.  

PubMed

Large quantities of mineral dust particles are frequently ejected into the atmosphere through the action of wind. The surface of dust particles acts as a sink for many gases, such as sulfur dioxide. It is well known that under most conditions, sulfur dioxide reacts on dust particle surfaces, leading to the production of sulfate ions. In this report, for specific atmospheric conditions, we provide evidence for an alternate pathway in which a series of reactions under solar UV light produces first gaseous sulfuric acid as an intermediate product before surface-bound sulfate. Metal oxides present in mineral dust act as atmospheric photocatalysts promoting the formation of gaseous OH radicals, which initiate the conversion of SO(2) to H(2)SO(4) in the vicinity of dust particles. Under low dust conditions, this process may lead to nucleation events in the atmosphere. The laboratory findings are supported by recent field observations near Beijing, China, and Lyon, France. PMID:23213230

Dupart, Yoan; King, Stephanie M; Nekat, Bettina; Nowak, Andreas; Wiedensohler, Alfred; Herrmann, Hartmut; David, Gregory; Thomas, Benjamin; Miffre, Alain; Rairoux, Patrick; D'Anna, Barbara; George, Christian

2012-12-18

212

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

213

Energy conversion by spontaneously reacting Li?SO 2 cells  

NASA Astrophysics Data System (ADS)

In abuse tests Li?SO 2 cells were exploded in a detonation chamber and in calorimeters. The energy measurements show that when air is present, the energy released is six times that obtained by electrically discharging the cells. In the absence of air the energy is reduced to one third. Reactions which may perhaps occur in the two cases are described and the heats of reaction are calculated. The calculated values are in fair agreement with those obtained experimentally. By comparing the pressure increase, it has been shown that the cell explosion is not as fast as the detonation of TNT. It is, however, faster than the combustion of the gunpowder used for comparison.

Våland, T.; Eriksen, S.

214

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

215

Plume velocity determination for volcanic SO2 flux measurements  

NASA Astrophysics Data System (ADS)

Ground based volcanic SO2 fluxes provide important insights into the behaviour of volcanoes, and their impacts upon the atmosphere. In order to compute a flux, the plume transport speed, and direction, must be known. In practice these are typically assumed to equal, respectively: (A) a ground based anemometer reading, and (B) the bearing of the vector between the volcanic gas source and the position on the downwind plume cross-section where the gas concentration is highest. However, use of these proxies is open to question, and they can introduce large errors (possibly > 100%), thereby significantly reducing the utility of the derived fluxes. Here we present direct spectroscopic measurements of volcanic plume velocity; the data were obtained using three ultraviolet spectrometers, at Masaya volcano, Nicaragua, during January 2004. We estimate that flux measurements with overall error budgets < 10% are readily achievable with this approach.

McGonigle, A. J. S.; Hilton, D. R.; Fischer, T. P.; Oppenheimer, C.

2005-06-01

216

forced overdischarge related safety aspects of Li/SO2 and Li/SOCl2 cells  

NASA Technical Reports Server (NTRS)

Results of an experiment investigating overdischarge behavior of two types of Li/SO2 cells are presented. Forced overdischarges of the Li/LiBr, CH3CN/SO2 cell can result in unsafe behavior such as venting with fire and release of toxic gases. The hazards may be minimized or eliminated by careful cell design considerations and practice of high standards of quality contol in cell manufacture. Seemingly safe cells at 25 C when forced overdischarged at -25 C, even at low currents, exhibited incipient signs of hazards. Their cathodes indicated signs of shock sensitivity. Cathode limited Li/SOCl2 cells were safe during forced overdischarge for long periods of time. Lithium limited Li/SOCl2 cells in which practically all Li had been used up before cell reversal did not exhibit hazardous behavior. Anode limited Li/SOCl2 cells, but not Li limited, exhibited detonations, all during overdischarges at relatively low current densities of or = 1 mA/sq cm 2. Anode potentials 4v with large oscillations preceeded the events. The events were confined to the anode and the temperature rose high enough to melt Ni grids.

Abraham, K. M.

1983-01-01

217

Mineral dust photochemistry induces nucleation events in the presence of SO2  

NASA Astrophysics Data System (ADS)

Every year, approximately 2000 Tg of mineral dust particles are released into the Earth's atmosphere. The surfaces of these particles act as a sink for many atmospheric gases, such as sulphur dioxide, which is believed to undergo reactions on the dust surface producing sulphate ions. However, flow tube experiments performed in the present study show that, under ultraviolet light, this reaction proceeds through a different pathway, producing gaseous sulphuric acid rather than surface-bound sulphate. We suggest that the metal oxides present in mineral dust serve as photocatalysts that promote the formation of OH radicals, which diffuse to the gas phase where they initiate the conversion of SO2 to H2SO4. These experiments suggest a revision of current knowledge : the chemical interactions of SO2 in the presence of mineral dust and solar illumination may lead to the nucleation of new particles in the atmosphere. These laboratory findings are supported by recent field observations near Beijing (China) and Lyon (France).

George, C.; Dupart, Y.; D'anna, B.; Nekat, B.; Herrmann, H.; Rairoux, P.; Miffre, A.; David, G.; Thomas, B.

2012-12-01

218

A field evaluation of a SO 2 passive sampler in tropical industrial and urban air  

NASA Astrophysics Data System (ADS)

Passive samplers have been widely used for over 30 years in the measurement of personal exposure to vapours and gases in the workplace. These samplers have just recently been applied in the monitoring of ambient air, which presents concentrations that are normally much smaller than those found in occupational environments. The locally constructed passive sampler was based on gas molecular diffusion through static air layer. The design used minimizes particle interference and turbulent diffusion. After exposure, the SO 2 trapped in impregnated filters with Na 2CO 3 was extracted by means of an ultrasonic bath, for 15 min, using 1.0×10 -2 mol L -1 H 2O 2. It was determined as SO 4-2 by ion chromatography. The performance of the passive sampler was evaluated at different exposure periods, being applied in industrial and urban areas. Method precision as relative standard deviation for three simultaneously applied passive samplers was within 10%. Passive sampling, when compared to active monitoring methods under real conditions, used in urban and industrial areas, showed an overall accuracy of 15%. A statistical comparison with an active method was performed to demonstrate the validity of the passive method. Sampler capacity varied between 98 and 421 ?g SO 2 m -3 for exposure periods of one month and one week, respectively, which allows its use in highly polluted areas.

Cruz, Lícia P. S.; Campos, Vânia P.; Silva, Adriana M. C.; Tavares, Tania M.

219

40 CFR Appendix C to Part 72 - Actual 1985 Yearly SO2 Emissions Calculation  

Code of Federal Regulations, 2013 CFR

...SO2) is as follows: SO2 = (coal SO2 emissions) + (oil SO2...yearly fuel burned) For coal, the yearly fuel burned is in...factor (which accounts for the ash retention of sulfur in coal), in lbs SO2 ton coal,...

2013-07-01

220

The use of vacuum ultraviolet irradiation to oxidize SO2 and NOx for simultaneous desulfurization and denitrification.  

PubMed

A simple and efficient method for simultaneous desulfurization and denitrification via vacuum ultraviolet (VUV) irradiation and with no additional chemicals is presented. The simultaneous removal of 90% SO2 and 96% NOx (NO+NO2) was achieved from the simulated flue gas under the irradiation from a low-pressure mercury lamp with main wavelengths of 185 and 254nm, respectively. The composition, flow rate, and temperature of the simulated flue gas, as well as the VUV light intensity, were evaluated as the factors impacting on the efficiency of SO2 and NOx removal. The OH, HO2, O, and O3 produced from the photolysis of H2O and O2 were concluded as the major reactive oxygen species that oxidized SO2 and NOx. The additional OH and HO2 generated through the reactions of NO+HO2 and SO2+OH/HO2 improved treatment efficiency, while the oxidation products of NOx, e.g., NO2, HNO2, HNO3, and HNO4, consumed massive reactive oxygen species (such as O, OH, and HO2) and thereby reducing the removal efficiencies. The main reaction products were characterized as H2SO4 and HNO3 by ion chromatography, which could be used as chemical or fertilizer raw materials. PMID:24632363

Ye, Junhui; Shang, Jing; Li, Qian; Xu, Weiwei; Liu, Jia; Feng, Xiang; Zhu, Tong

2014-04-30

221

Diffusion Coefficients of SO2 in Water and Partition Coefficients of SO2 in Water-Air Interface at Different Temperature and pH Values  

Microsoft Academic Search

Reversed flow gas chromatography was applied to measure the diffusion coefficient of SO2 in water, the partition coefficient of SO2 in air–water interface, and the rate constant, kR, for chemical reaction between SO2 and water at various temperature and pH values. A linear increment of the diffusion coefficients of SO2 in water with temperature is drawn while the partition coefficients

A. Koliadima; J. Kapolos; L. Farmakis

2009-01-01

222

Proceedings: Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies (1st). Volume 1. Fundamental Research and Process Development.  

National Technical Information Service (NTIS)

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 re...

P. J. Chappell

1985-01-01

223

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...

224

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

225

Evaluation of reactive gases simulations using updated emission inventories in the framework of the MACC project  

NASA Astrophysics Data System (ADS)

The goal of this study is to assess the simulations of the distribution of the reactive gases using satellite observations. It will further help to assess the emission inventories used in simulations. This work is the part of the European 7th framework project MACC (Monitoring Atmopsheric Composition and Climate). Within MACC, several anthropogenic emission inventories have been updated, however, we will focus only on CO, NO2, HCHO and SO2 emission distributions. We will evaluate the distribution of these reactive and precursor gases as calculated by three chemistry transport models involved in MACC project i.e. MOZART, TM5 and MOCAGE. These simulation outputs are evaluated by comparing with ground based and satellite observations. We will present a case study focusing mainly on SO2 emissions from non-ferrous metal smelting industry located in Peru ( Ilo and La Oroya smelters) and in Siberia (Norilsk smelter). We will discuss the methodology we have used to improve the emissions from these smelters by using satellite observations of SO2 from SCIAMACHY instrument onboard ENVISAT-1. We will show that a significant improvement has been obtained in the MOZART simulation outputs when the updated SO2 emission fields are used by the model.

Fahim Khokhar, Muhammad; Granier, C.; Law, K.; Stein, O.; Schultz, M.; Peuch, V. H.; Huijen, V.

2010-05-01

226

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

227

Reaction of monoterpenes with ozone, sulphur dioxide and nitrogen dioxide—gas-phase oxidation of SO 2 and formation of sulphuric acid  

NASA Astrophysics Data System (ADS)

Teflon bag experiments were carried out in the dark in order to study the gas-phase reactions of selected monoterpenes with O 3 in the presence of SO 2 (?-pinene) as well as in the presence of SO 2/NO 2 (?-pinene, ?-pinene, limonene). Emphasis was given in identifying the main reaction products and in quantifying the H 2SO 4 aerosol formed. Apart from the H 2SO 4 aerosol no other S containing compounds could be detected. It was found that the reaction of ?-pinene with O 3, SO 2 and NO 2 leads mainly to 6,6-dimethyl-bicyclo [3.1.1] heptan-2-one (nopinone), the ?-pinene-O 3-SO 2-NO 2-reaction produced 2',2'-dimethyl-3-acetyl cyclobutyl ethanal (pinonaldehyde). The reaction of limonene with O 3-SO 2-NO 2 leads mainly to an unidentified product with a molecular weight M + 134. In addition to the above-mentioned volatile products, the formation of organic nitrates could be established by means of gas chromatography-mass spectrometry. The yield of H 2SO 4 in the system ?-pinene/O 3/SO 2 varies between 0.13 and 0.44 depending on the initial conditions, e.g. humidity. In the system terpene/O 3/SO 2/NO 2 the yield of H 2SO 4 for ?-pinene (after 1 h reaction time) was 0.01-0.03, for ?-pinene (2 or 4 h reaction time) 0.07-0.13 and for limonene (1 h reaction time) 0.02-0.09.

Kotzias, D.; Fytianos, K.; Geiss, F.

228

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

229

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

230

The SO2 Camera: A Simple, Fast and Cheap Method for Ground-based Imaging of SO2 in Volcanic Plumes  

NASA Astrophysics Data System (ADS)

SO2 flux is widely monitored on active volcanoes as it gives a window into the hidden, subsurface magma dynamics. We present here a new approach to SO2 flux monitoring using ultraviolet imaging of the volcanic plume through carefully chosen filters to produce images of SO2 amount. The configuration of the instrument, SO2 camera, is very simple and consists of three parts: A CCD camera, UV lens and a filter holder unit. The imaging system used was an Alta-U260 (Apogee Instr. Inc.) with 512 x 512 pixels CCD. The filter holder unit has two UV band path filters centered at 310 and 330 nm with 10 nm FWHM (Asahi bunko Inc.) and is able to change the filters alternately. The images of SO2 amount were retrieved by processing images obtained using the two filters. The SO2 camera was tested at Sakurajima volcano, Japan on November 18, 2005. Our test was conducted on a clear day at Harutayama observatory, 2.8 km north-west of currently active crater. Sixty images of SO2 amount were retrieved with a time interval of ~5.7 s between 14:06 and 14:12 local time. The aim of the SO2 camera is to allow high time-resolution measurements of SO2 flux, calculated with internally consistent wind speeds. The SO2 flux was calculated by integrating path amounts of one line in an SO2 image perpendicular to the wind direction. Wind speed was derived using cross- correlations calculated for two SO2 profiles in the images. The temporal variation of SO2 flux between 14:06 and 14:12 was obtained with high time resolution of ~5.7 s. We observed the flux change from 1.2 kg/s to 5.8 kg/s in only ~35 s during the period. The SO2 camera heralds a breakthrough in both our ability to measure SO2 flux at unprecedented frequencies and at unprecedented precision, thanks to the application of correlation techniques to determine wind speed directly from the images. In this presentation, we detail the commercially available pieces required to construct the SO2 camera, introduce a retrieval scheme to determine SO2 amounts from the images. We present results from a field campaign in November 2005 on Sakurajima volcano and from other recent field campaigns. We believe that the SO2 camera represents a significant step forward in our ability to monitor volcanic gas emissions, and in the coming months and years will yield substantial results to volcanological monitoring.

Mori, T.; Burton, M.

2006-12-01

231

40 CFR 97.711 - Timing requirements for TR SO2 Group 2 allowance allocations.  

Code of Federal Regulations, 2013 CFR

...false Timing requirements for TR SO2 Group 2 allowance allocations. 97.711...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.711 Timing requirements for TR SO2 Group 2 allowance allocations. (a)...

2013-07-01

232

40 CFR 97.712 - TR SO2 Group 2 allowance allocations to new units.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false TR SO2 Group 2 allowance allocations to new units. 97...AND CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.712 TR SO2 Group 2 allowance allocations to new units....

2013-07-01

233

40 CFR 97.612 - TR SO2 Group 1 allowance allocations to new units.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false TR SO2 Group 1 allowance allocations to new units. 97...AND CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.612 TR SO2 Group 1 allowance allocations to new units....

2013-07-01

234

40 CFR 97.723 - Recordation of TR SO2 Group 2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 2 allowance transfers. 97.723 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.723 Recordation of TR SO2 Group 2 allowance transfers. (a)...

2013-07-01

235

40 CFR 97.622 - Submission of TR SO2 Group 1 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Submission of TR SO2 Group 1 allowance transfers. 97.622 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.622 Submission of TR SO2 Group 1 allowance transfers. (a) An...

2013-07-01

236

40 CFR 97.724 - Compliance with TR SO2 Group 2 emissions limitation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Compliance with TR SO2 Group 2 emissions limitation. 97.724 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.724 Compliance with TR SO2 Group 2 emissions limitation. (a)...

2013-07-01

237

40 CFR 97.624 - Compliance with TR SO2 Group 1 emissions limitation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Compliance with TR SO2 Group 1 emissions limitation. 97.624 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.624 Compliance with TR SO2 Group 1 emissions limitation. (a)...

2013-07-01

238

40 CFR 97.611 - Timing requirements for TR SO2 Group 1 allowance allocations.  

Code of Federal Regulations, 2013 CFR

...false Timing requirements for TR SO2 Group 1 allowance allocations. 97.611...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.611 Timing requirements for TR SO2 Group 1 allowance allocations. (a)...

2013-07-01

239

40 CFR 97.623 - Recordation of TR SO2 Group 1 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 1 allowance transfers. 97.623 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.623 Recordation of TR SO2 Group 1 allowance transfers. (a)...

2013-07-01

240

40 CFR 97.722 - Submission of TR SO2 Group 2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Submission of TR SO2 Group 2 allowance transfers. 97.722 Section...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.722 Submission of TR SO2 Group 2 allowance transfers. (a) An...

2013-07-01

241

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...

242

Simultaneous absorption of NOx and SO2 from flue gas with pyrolusite slurry combined with gas-phase oxidation of NO using ozone.  

PubMed

NO was oxidized into NO(2) first by injecting ozone into flue gas stream, and then NO(2) was absorbed from flue gas simultaneously with SO(2) by pyrolusite slurry. Reaction mechanism and products during the absorption process were discussed in the followings. Effects of concentrations of injected ozone, inlet NO, pyrolusite and reaction temperature on NO(x)/SO(2) removal efficiency and Mn extraction rate were also investigated. The results showed that ozone could oxidize NO to NO(2) with selectivity and high efficiency, furthermore, MnO(2) in pyrolusite slurry could oxidize SO(2) and NO(2) into MnSO(4) and Mn(NO(3))(2) in liquid phase, respectively. Temperature and concentrations of injected ozone and inlet NO had little impact on both SO(2) removal efficiency and Mn extraction rate. Specifically, Mn extraction rate remained steady at around 85% when SO(2) removal efficiency dropped to 90%. NO(x) removal efficiency increased with the increasing of ozone concentration, inlet NO concentration and pyrolusite concentration, however, it remained stable when reaction temperature increased from 20°C to 40°C and decreased when the flue gas temperature exceeded 40°C. NO(x) removal efficiency reached 82% when inlet NO at 750 ppm, injected ozone at 900 ppm, concentration of pyrolusite at 500 g/L and temperature at 25°C. PMID:21620564

Sun, Wei-yi; Ding, Sang-lan; Zeng, Shan-shan; Su, Shi-jun; Jiang, Wen-ju

2011-08-15

243

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

244

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; Daughtry, Craig

1995-09-01

245

Temperature effect on ultraviolet differential absorption cross section of SO2  

NASA Astrophysics Data System (ADS)

When the technique of differential optical absorption spectroscopy (DOAS) is applied to the pollutant monitoring, the differential absorption characteristics of pollution gases will change greatly owing to the flue gas is often with high temperature. This will bring the influence on the detection results. This article mainly aims at the temperature effects for SO2 differential absorption cross section by recordings the absorption spectra. The results show that the differential absorption property changes dramatically with temperature. The differential absorption peaks in the region of 280.0-320.0nm decrease with the increase of temperature while the valleys will increase. So the entire differential absorption cross section decreases with the increase of temperature, but no wavelength drift and differential absorption structure change appear with temperature. By measuring the differential absorption cross section of a few peaks at different temperature, it is found that the reduction regularity at different wavelength is varied. The variation at 286.7nm, 293.9nm and 304.0nm with temperature is in a manner of cubic polynomial, while the variation at 300.0nm presents a nearly linear decline. When the temperature rises from 300K to 450K, the relative change of the differential absorption cross section at 286.7nm is 77.1%, while it can reach 84.0% at 300.0nm.

Jin, Weijia; Zheng, Haiming; Li, Haiping; Zhang, Guiyin; Ji, Hui

2012-11-01

246

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...

247

Proceedings: Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies (1986). Volume 2. Economics, Power Plant Intergration and Commercial Applications.  

National Technical Information Service (NTIS)

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 manufa...

B. Emmel

1986-01-01

248

Proceedings: Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies (1st): Volume 2. Power Plant Integration, Economics, and Full-Scale Experience.  

National Technical Information Service (NTIS)

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...

P. J. Chappell

1985-01-01

249

Proceedings: Joint Symposium on Dry SO2 and Simultaneous SO2/NOx Control Technologies (1986). Volume 1. Sorbents, Process Research, and Dispersion.  

National Technical Information Service (NTIS)

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 manufa...

B. Emmel

1986-01-01

250

Adsorption of SO2 and NO from incineration flue gas onto activated carbon fibers.  

PubMed

Activated carbon fibers (ACFs) were used to remove SO2 and NO from incineration flue gas. Three types of ACFs in their origin state and after pretreatment with HNO3, NaOH, and KOH were investigated. The removal efficiencies of SO2 and NO were determined experimentally at defined SO2 and NO concentrations and at temperatures of 150, 200 and 260 degrees C. Experimental results indicated that the removal efficiencies of SO2 and NO using the original ACFs were < 56% and < 27%, respectively. All ACFs modified with HNO3, NaOH, and KOH solution could increase the removal efficiencies of SO(2) and NO. The mesopore volumes and functional groups of ACFs are important in determining the removal of SO2 and NO. When the mesopore volumes of the ACFs are insufficient for removing SO2 and NO, the functional groups on the ACFs are not important in determining the removal of SO2 and NO. On the contrary, the effects of the functional groups on the removal of SO2 and NO are more important than the mesopore volumes as the amount of mesopores on the ACFs is sufficient to remove SO2 and NO. Moreover, the removal efficiencies of SO2 and NO were greatest at 200 degrees C. When the inlet concentration of SO2 increased to 600 ppm, the removal efficiency of SO2 increased slightly and the removal efficiency of NO decreased. PMID:18083361

Liu, Zhen-Shu

2008-11-01

251

Infrared absorption of CH3SO2 observed upon irradiation of a p-H2 matrix containing CH3I and SO2  

NASA Astrophysics Data System (ADS)

Irradiation with a mercury lamp at 254 nm of a p-H2 matrix containing CH3I and SO2 at 3.3 K, followed by annealing of the matrix, produced prominent features at 633.8, 917.5, 1071.1 (1072.2), 1272.5 (1273.0, 1273.6), and 1416.0 cm-1, attributable to ?11 (C-S stretching), ?10 (CH3 wagging), ?8 (SO2 symmetric stretching), ?7 (SO2 antisymmetric stretching), and ?4 (CH2 scissoring) modes of methylsulfonyl radical (CH3SO2), respectively; lines listed in parentheses are weaker lines likely associated with species in a different matrix environment. Further irradiation at 365 nm diminishes these features and produced SO2 and CH3. Additional features at 1150.1 and 1353.1 (1352.7) cm-1 are tentatively assigned to the SO2 symmetric and antisymmetric stretching modes of ISO2. These assignments are based on comparison of observed vibrational wavenumbers and 18O- and 34S-isotopic shifts with those predicted with the B3P86 method. Our results agree with the previous report of transient IR absorption bands of gaseous CH3SO2 at 1280 and 1076 cm-1. These results demonstrate that the cage effect of solid p-H2 is diminished so that CH3 radicals, produced via UV photodissociation of CH3I in situ, might react with SO2 to form CH3SO2 during irradiation and upon annealing. Observation of CH3SO2 but not CH3OSO is consistent with the theoretical predictions that only the former reactions proceed via a barrierless path.

Lee, Yu-Fang; Lee, Yuan-Pern

2011-03-01

252

Investigation on the solubility of SO2 and CO2 in imidazolium-based ionic liquids using NPT Monte Carlo simulation.  

PubMed

The solubility of sulfur dioxide (SO(2)) and carbon dioxide (CO(2)) at P = 1 bar in a series of imidazolium-based room-temperature ionic liquids (RTILs) is calculated by Monte Carlo simulation in NPT ensemble using the OPLS-UA force field and Widom particle insertion method. The studied ILs were 1-butyl-3-methylimidazolium ([bmim](+)) tetrafluoroborate ([BF(4)](-)), [bmim](+) hexafluorophosphate ([PF(6)](-)), [bmim](+) bromide ([Br](-)), [bmim](+) nitrate ([NO(3)](-)), [bmim](+) bis-(trifluoromethyl) sulfonylimide ([Tf2N](-)), and 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF(4)]). To validate the simulations, the liquid density of studied ILs and the solubility of CO(2) in [bmim][PF(6)] was compared with corresponding experimental and theoretical studies reported in the literature, and a good agreement was obtained. The results of SO(2) solubility demonstrate that the SO(2) gas has the highest solubility in [bmim][NO(3)] and [bmim][Br] ILs and the lowest solubility in [bmim][PF(6)]. To describe the solubility order of polar gases such as SO(2) and nonpolar gases like CO(2), we have simulated the SO(2)/IL and CO(2)/IL mixtures which made possible to investigate the interaction of solute molecules with anions and cations in the liquid phase. We introduced the ratio of solute-IL interaction over cation-anion interaction energy density as an index for solubility of gases in ILs. The results show that the proposed index can describe the solubility order of SO(2) as well as CO(2) and it might be used as an alternative to standard methods of infinite dilution Henry's constant calculations when the solubility order is desired. PMID:21955274

Ghobadi, Ahmadreza F; Taghikhani, Vahid; Elliott, J Richard

2011-11-24

253

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

Code of Federal Regulations, 2010 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

254

Recent SO2 camera and OP-FTIR field measurements in Mexico and Guatemala  

NASA Astrophysics Data System (ADS)

Between 22 and 30 November 2012 a field campaign was carried out at Mexico and Guatemala with the objectives of state the volcanic gas composition and flux fingerprints of Popocatepetl, Santiaguito, Fuego and Pacaya by exploiting simultaneously UV-camera and FTIR measurements. Gases were measured remotely using instruments sensitive to ultraviolet and infrared radiation (UV spectrometer, SO2-camera and OP-FTIR). Data collection depended on the requirements of the methodology, weather condition and eruptive stage of the volcanoes. OP-FTIR measurements were carried out using the MIDAC interferometer with 0.5 cm-1 resolution. Spectra were collected in solar occultation mode in which the Sun acts as an infrared source and the volcanic plume is interposed between the Sun and the spectrometer. At Santiaguito spectra were also collected in passive mode using the lava flow as a radiation source. The SO2-camera used for this study was a dual camera system consisting of two QS Imaging 640s cameras. Each of the two cameras was outfitted with two quartz 25mm lens, coupled with two band-pass filters centred at 310nm and at 330nm. The imaging system was managed by a custom-made software developed in LabView. The UV-camera system was coupled with a USB2000+ spectrometer connected to a QP1000-2-SR 1000 micron optical fiber with a 74-UV collimating lens. For calibration of plume imagery, images of five quartz cells containing known concentration path-lengths of SO2 were taken at the end of each sampling. Between 22 and 23 November 2012 UV-camera and FTIR observations were carried out at Popocatepetl. During the time of our observation, the volcano was characterised by pulsing degassing from the summit crater forming a whitish plume that dispersed rapidly in the atmosphere according to wind direction and speed. Data were collected from the Observatorio Atmosférico Altzomoni (Universidad Nacional Autónoma de México) at 4000 metre a.s.l. and at a distance of ~12 km from the volcano summit. SO2 camera observations were made for ~30 and 130 minutes on the 22 and 23 November, respectively, with a sampling rate of ~7 seconds. FTIR measurements were carried out for 20 and 15 minutes on 22 and 23 November. At Santiaguito volcano, we carried out volcanic gas measurements on 27 and 28 November 2012. During the period of our observations the volcano activity was characterised by lava flow extrusion on the S flank of dome edifice. Occasionally, incandescent blocks detached from the lava flow front rolling onto the dome flanks. During the time of our survey the explosive activity was low frequency (every ~5 - 6 hours). We observed a persistent and sustained degassing plume was observed occasionally polluted by ash. However, on 28 November at 5:25 local time, a violent pyroclastic flow occurred generating an ash-plume that rose ~5 km passing Santa Maria's summit and spreading ~30 km south. SO2 camera and FTIR data were simultaneously collected on 27 November from El Mirador at a distance of ~2 Km from the lava-dome. Data were collected for ~75 and ~90 minutes for SO2-camera and FTIR, respectively. On 28 November, due to the pyroclastic flow event, only distal solar occultation FTIR measurements and open-path UV spectra (using a USB spectrometer) were collected from the west flank of Santa Maria volcano. Both UV and IR spectra were recorded for ~60 minutes Ash released by the pyroclastic flow was sampled from a distance of 6.5 km from the volcano collecting the fallout products along a 60 minute time interval Data from the volcanic plumes of Pacaya and Fuego were collected on 29 and 30 November 2012. During our survey the eruptive activity of Pacaya consisted of weak puffing from the summit crater, while Fuego showed a weak outgassing occasionally interrupted by explosion from its summit crater. In both days, we carried out only SO2 camera measurements due to the poor weather conditions which prevented solar FTIR measurments. At both volcanoes, UV images were taken for a period of ~45 minutes from a distance of ~ 3 km and ~ 10 km, respectively. In th

La Spina, Alessandro; Salerno, Giuseppe; Burton, Michael

2013-04-01

255

A rapid deployment instrument network for temporarily monitoring volcanic SO2 emissions - a study case from Telica volcano  

NASA Astrophysics Data System (ADS)

Volcanic gas emissions play a crucial role in describing geophysical processes; hence measurements of magmatic gases such as SO2 can be used as tracers prior and during volcanic crises. Different measurement techniques based on optical spectroscopy have provided valuable information when assessing volcanic crises. This paper describes the design and implementation of a network of spectroscopic instruments based on Differential Optical Absorption Spectroscopy (DOAS) for remote sensing of volcanic SO2 emissions, which is robust, portable and can be deployed in relative short time. The setup allows the processing of raw data in situ even in remote areas with limited accessibility, and delivers pre-processed data to end-users in near real time even during periods of volcanic crisis, via a satellite link. In addition, the hardware can be used to conduct short term studies of volcanic plumes in remotes areas. The network was tested at Telica, an active volcano located in western Nicaragua, producing what is so far the largest data set of continuous SO2 flux measurements at this volcano.

Conde, V.; Nilsson, D.; Galle, B.; Cartagena, R.; Muñoz, A.

2014-04-01

256

Temporal variability in SO 2 exposures at Hawai’i Volcanoes National Park, USA  

Microsoft Academic Search

Sulfur dioxide measured at the Visitor’s Center of Hawai’i Volcanoes National Park, USA exhibits seasonal and diurnal patterns\\u000a and is sensitive to rainfall, but the relationship between wind direction and SO2 is too inconsistent to support deterministic predictions of hourly SO2 based on hourly wind direction. Although SO2 at the Visitor Center has usually been below regulatory levels, high SO2

Jene D. Michaud; Jon-Pierre Michaud; Dmitry Krupitsky

2007-01-01

257

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

258

The Rotational Spectrum of SO(2) and the Determination of the Hyperfine Constants and Nuclear Magnetic Shielding Tensors of (33)SO(2) and SO(17)O.  

PubMed

Precise frequencies for the 1(11)-2(02) transition of (33)SO(2) and SO(17)O in natural isotopic abundance have been obtained near 12 GHz by microwave Fourier transform spectroscopy in order to yield improved hyperfine constants. Nuclear spin-rotation coupling constants have been determined experimentally for (33)SO(2) for the first time. The spin-rotation constants have been used to derive nuclear magnetic shielding parameters. These parameters are compared with values for the isoelectronic O(3) molecule. The transition mentioned above was also measured for (32)SO(2), (34)SO(2), SO(18)O, and vibrationally excited (v(2) = 1) (32)SO(2). For (33)SO(2), some transitions with large hyperfine splitting were also recorded in the millimeter-wave region. Continuing our investigations of the rotational spectra of SO(2) in the submillimeter region, several transitions of SO(17)O have been recorded with the Cologne terahertz spectrometer between 540 and 840 GHz with J and K(a) up to 63 and 16, respectively. Transitions with high K(a), up to 28, have been recorded with the JPL laser sideband spectrometer between 1.8 and 3.2 THz. Copyright 2000 Academic Press. PMID:10753605

Müller; Farhoomand; Cohen; Brupbacher-Gatehouse; Schäfer; Bauder; Winnewisser

2000-05-01

259

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 ...

260

Linking volcanic tremor, degassing, and eruption dynamics via SO2 imaging  

Microsoft Academic Search

Recently developed UV cameras offer improvement in remote sensing of volcanic SO2, with temporal resolutions of ?1 Hz and synoptic plume views. Integrated UV camera and seismic measurements recorded in January 2009 at Fuego volcano, Guatemala, provide new insight into the system's shallow conduit processes. High temporal resolution SO2 data reveal patterns of SO2 emission rate relative to explosions and

Patricia A. Nadeau; José L. Palma; Gregory P. Waite

2011-01-01

261

REACTIVATION OF SOLIDS FROM FURNACE INJECTION OF LIMESTONE FOR SO2 CONTROL  

EPA Science Inventory

The paper gives results of a characterization of post-furnace injection solids and flyash mixtures and their testing in a bench-scale reactor for the removal of SO2. Virtually no SO2 removal was observed with untreated solids. High SO2 capture occurred when the samples were hydra...

262

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

Code of Federal Regulations, 2012 CFR

...contain SO2 in excess of 50 percent (0.50) of the potential SO2 emission rate...contain SO2 in excess of 215 ng/J (0.50 lb/MMBtu) heat input from oil...lb/MMBtu); Kc = 215 ng/J (0.50 lb/MMBtu); Ha = Heat...

2012-07-01

263

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

Code of Federal Regulations, 2010 CFR

...contain SO2 in excess of 50 percent (0.50) of the potential SO2 emission rate...contain SO2 in excess of 215 ng/J (0.50 lb/MMBtu) heat input; or, as an...lb/MMBtu); Kc = 215 ng/J (0.50 lb/MMBtu); Ha = Heat...

2010-07-01

264

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

Code of Federal Regulations, 2011 CFR

...contain SO2 in excess of 50 percent (0.50) of the potential SO2 emission rate...contain SO2 in excess of 215 ng/J (0.50 lb/MMBtu) heat input; or, as an...lb/MMBtu); Kc = 215 ng/J (0.50 lb/MMBtu); Ha = Heat...

2011-07-01

265

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

266

Dissociation dynamics of the methylsulfonyl radical and its photolytic precursor CH3SO2Cl  

NASA Astrophysics Data System (ADS)

The dissociation dynamics of methylsulfonyl radicals generated from the photodissociation of CH3SO2Cl at 193 nm is investigated by measuring product velocities in a crossed laser-molecular beam scattering apparatus. The data evidence three primary photodissociation channels of the precursor: S-Cl fission to produce Cl atoms and ground electronic state CH3SO2 radicals, S-Cl fission to produce Cl atoms and electronically excited CH3SO2 radicals, and S-CH3 fission. Some of the vibrationally excited CH3SO2 radicals undergo subsequent dissociation to CH3+SO2, as do all of the electronically excited radicals. The velocities of the SO2 products show that the vibrationally excited ground state CH3SO2 radicals dissociate via a loose transition state having a small exit barrier beyond the endoergicity. Hence, a statistical recoil kinetic energy distribution should and does fit the distribution of velocities imparted to these SO2 products. The electronically excited CH3SO2 radicals also dissociate to CH3+SO2, but with a larger average release to relative kinetic energy. Interestingly, when using 200 eV electron bombardment detection, the ground electronic state CH3SO2 radicals having too little internal energy to dissociate are not observed at the parent CH3SO2+ ion, but only at the CH3+ daughter ion. They are distinguished by virtue of the velocity imparted in the original photolytic step; the detected velocities of the stable radicals are consistent with the calculated barrier of 14.6 kcal/mol for the dissociation of CH3SO2 to CH3+SO2. We present CCSD(T) calculations of the adiabatic excitation energy to the lowest excited state of CH3SO2 radicals, the 1 2A'' state, as well as the vertical energy from the equilibrium geometry of that excited state to the 2 2A'' state, to aid in the experimental assignment.

Alligood, Bridget W.; Fitzpatrick, Benjamin L.; Glassman, Emily Jane; Butler, Laurie J.; Lau, Kai-Chung

2009-07-01

267

Validation of OMI Satellite Measurements of SO2 by Ground-based MFDOAS Spectroscopy During the Okmok Volcanic Eruption in July 2008  

NASA Astrophysics Data System (ADS)

The Dutch-Finnish Ozone Monitoring Instrument (OMI) on board the NASA Aura satellite measures a suite of trace gases including SO2. Since its launch in July 2004, OMI has made many measurements of SO2 including natural sources such as explosive and effusive volcanic eruptions and volcanic passive degassing, and human sources such as coal power plants, metal smelters, and oil refineries. Validation of these measurements is very difficult because of OMI reduced sensitivity to SO2 in the planetary boundary layer and the transient nature of volcanic plumes. The recent eruption of the Okmok volcano in the Aleutian islands provided a unique opportunity for high quality validation because the plume spent several days moving over a research-grade ground-based spectrometer located in Washington state, the multi-function differential absorption spectroscopy (MFDOAS) instrument. This instrument provided accurate determinations of column abundance of SO2 in the Okmok plume using the direct sun as a source with an estimated accuracy less than 0.2 DU, which is an order of magnitude better than data from the operational Brewer spectrophotometer network. We discuss our instrumentation, data reduction technique and SO2 time series results during 2 days of observations of the Okmok plume over Pullman, WA. Measured SO2 column amount ranged from 0.5 DU to 5DU ( 1 DU, Dobson Unit =2.69*10**16 molecules/cm**2) due to inhomogeneity of the plume. Direct overpass comparison with OMI shows good qualitative agreement with OMI operational low stratospheric SO2 data. Corrections for the OMI field of view, SO2 plume height, and temperature improve agreement further as well as comparisons with the off-line Iterative Spectral Fit (ISF) algorithm. This case study provides critical validation of the volcanic OMI SO2 measurements.

Spinei, E. C.; Carn, S.; Krotkov, N.; Yang, K.; Krueger, A.; Bhartia, P. K.; Mount, G. H.

2008-12-01

268

Greenhouse Gases  

MedlinePLUS

... were not for naturally occurring greenhouse gases, the Earth would be too cold to support life as ... the greenhouse effect, the average temperature of the Earth would be about -2°F rather than the ...

269

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

270

[Experiment study on the aqueous removal of SO2 by Mn2+ catalytic ozonation].  

PubMed

The removal of SO2 by Mn2+ catalytic aqueous ozonation was investigated by experiment, so as to find the effects of Mn2+ for aqueous removal of SO2 by ozonation. The concentration curve of ozone was drawn by standard iodine method. The operating factors included mole ratio of ozone to sulfur dioxide and concentration of Mn2+. When absorption solution has no Mn2+, the removal efficiency of SO2 was 35% at [O3 ]/[SO2 ] = 0.5,but the efficiency was 70% when Mn2+ was put into absorption solution at the same value of [O3 ]/[SO2].With the increasing of [3O]/[SO2], the removal efficiency of SO2 increases. And as concentration of Mn2+ increases, the efficiency also increases. There is an appropriate concentration range which is 1.2 x 10(-2)-1.2 x 10(-1) mol/L for Mn2+. PMID:20063725

Ma, Shuang-Chen; Su, Min; Ma, Jing-Xiang; Sun, Yun-Xue; Jin, Xin; Zhao, Yi

2009-11-01

271

Ambient Lithium-SO2 Batteries with Ionic Liquids as Electrolytes.  

PubMed

Li-SO2 batteries have a high energy density but bear serious safety problems that are associated with pressurized SO2 and flammable solvents in the system. Herein, a novel ambient Li-SO2 battery was developed through the introduction of ionic liquid (IL) electrolytes with tailored basicities to solvate SO2 by reversible chemical absorption. By tuning the interactions of ILs with SO2 , a high energy density and good discharge performance with operating voltages above 2.8?V were obtained. This strategy based on reversible chemical absorption of SO2 in IL electrolytes enables the development of the next generation of ambient Li-SO2 batteries. PMID:24446427

Xing, Huabin; Liao, Chen; Yang, Qiwei; Veith, Gabriel M; Guo, Bingkun; Sun, Xiao-Guang; Ren, Qilong; Hu, Yong-Sheng; Dai, Sheng

2014-02-17

272

Aerosol optical depth, backscattering profiles and column NO2 and SO2 measurements during March 2006 in Tenango del Aire, Mexico  

Microsoft Academic Search

The Tenango del Aire site (19.16°N, 98.86°W, 2380 masl) is located some 40 km SE from Mexico City in the Chalco Valley, where some pollution otflow has been predicted by air quality models. Direct and diffuse ground-based irradiance measurements have been made at this site during the MILAGRO field campaign by a UV-MultiFilter Rotating ShadowBand Radiometer (UV-MFRSR) at seven channels

A. Hernandez; R. Basaldud; M. Grutter; D. Baumgardner; J. Slusser; R. Steinbrecher; L. G. Ruiz-Suarez

2007-01-01

273

Potential Impacts of two SO2 oxidation pathways on regional sulfate concentrations: acqueous-hase oxidation by NO2 and gas-phase oxidation by Stabilized Criegee Intermediates  

EPA Science Inventory

We examine the potential impacts of two additional sulfate production pathways using the Community Multiscale Air Quality modeling system. First we evaluate the impact of the aqueous-phase oxidation of S(IV) by nitrogen dioxide using two published rate constants, differing by 1-2...

274

Removing arsenic from copper smelter gases  

Microsoft Academic Search

The pyrometallurgical processing of nonferrous minerals found in association with sulfur and arsenic generates arsenic-bearing\\u000a SO2 gases. Effective process gas cleaning presents technical problems due to the high volatility of the As2O3 compound and the elevated dew point of the sulfur-trioxidecontaining SO2 gas. Critical factors for gascleaning technology selection pertaining to technical feasibility, economic acceptability, and\\u000a environmental compatibility are the

Frank Dalewski

1999-01-01

275

A NOx and SO2 gas analyzer using deep-UV and violet light-emitting diodes for continuous emissions monitoring systems  

NASA Astrophysics Data System (ADS)

A nitrogen oxides (NOx) and sulfur dioxide (SO2) gas analyzer using deep ultraviolet (DUV) and violet light- emitting diodes (LEDs) is developed. The LEDs with wavelengths of 280 nm and 400 nm were alternately turned on to detect SO2 and nitrogen dioxide (NO2) absorption. Nitric oxide (NO) was converted to NO2 with an ozonizer. In order to reduce water interference caused by water adsorption onto an inner surface of a gas ow cell, collimating optics reducing re ected lights were designed. As a result, less than 1% by full scale (%F.S.) of uctuation, 2%F.S. of drift and 0.5%F.S. of water interference were achieved in 0-50 ppm concentration range. Conversion efficiency from NO to NO2 was over 95%.

Higashi, Ryoichi; Taniguchi, Yu; Akao, Kozo; Koizumi, Kazuhiro; Hirayama, Noritomo; Nakano, Yoshiaki

2014-02-01

276

Simultaneous SO2 and NO removal from flue gas based on TiO2 photocatalytic oxidation.  

PubMed

A new approach to the simultaneous removal of SO2 and NO from flue gas, by TiO2 photocatalysis based on UV irradiation technology, is presented. Experiments on the simultaneous desulphurization and denitrification were carried out using this photocatalyst in a self-designed photocatalytic reactor. Under the optimal experimental conditions, a removal efficiency of 98% for SO2 and 50% for NO was achieved. Scanning electron microscopy, transmission electron microscopy and X-ray energy spectrometry were used to observe the surface characteristics of the TiO2 photocatalyst. It was found that the surface of the quartz sand carrier was covered with Ti, on which the Si content of the quartz sand carrier was similar to the Ti content, indicating that the quartz sand supported the TiO2 membrane well. Based on the results of X-ray photoelectron spectroscopy (XPS) and chemical analysis of the resulting products, the SO2 and NO removal mechanisms were revealed. Sulphate was the main desulphurization product and nitrite was the main denitrification product. In the removal reaction, NO was rapidly oxidized to NO2 and absorbed in the chemical reaction. PMID:20184000

Zhao, Yi; Han, Jing; Shao, Yuan; Feng, Yana

2009-12-14

277

Evaluation of SO 2 oxidation and fly ash filtration by an activated carbon fluidized-bed reactor: The effects of acid modification, copper addition and operating condition  

Microsoft Academic Search

It is expected that the simultaneous removal of acid gases and particles from flue gas, using a single process and at the same temperature, will become an economical, and thus, desirable option. Accordingly, this study investigates the potential for the utilization of a fluidized-bed adsorbent\\/catalyst reactor for the simultaneous removal of SO2 and fly ash from simulated flue gas. The

Jui-Yeh Rau; Hui-Hsin Tseng; Bo-Chin Chiang; Ming-Yen Wey; Min-Der Lin

2010-01-01

278

A New Perspective about Recovering SO2 Offgas in Coal Power Plants: Energy Saving. Part III. Selection of the Best Methods  

Microsoft Academic Search

High-temperature desulfurization processes, for IGCC and other advanced electric power generation applications, utilize regenerable mixed-metal sorbents to remove reduced sulfur compounds from coal gasifier gases. In the desulfurization of the coal gas, the metals in the sorbent become sulfided. The off-gas from this regeneration process will contain from 1–3% SO2 (McMichael, 1991; Gangwal, 1991; Mojtahedi, 1994). This article presents an

F Tomás-Alonso

2005-01-01

279

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

280

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 2.11mol SO2 per mole IL (pure SO2) and 0.94mol 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

281

Use of plants to monitor contamination of air by SO2 in and around refinery.  

PubMed

The generation of SO2 from a refinery may affect the surrounding environment. Moreover, SO2 and its by-products are phytotoxic as berg. This study aims to investigate plant responses to SO2. The work has been designed with emphasis on using the plants directly in monitoring the contamination of the atmospheric air by SO2. An assessment was made of the impacts of long-term SO2 emissions from an oil refinery on plants located in nearby areas that are likely to be exposed to emission fallout. Three different plant species (Prosopis cineraria. Azadirachta indica, and Phoenix dactilifera) common to the environment of the Arabian Gulf were selected at different distances and directions from the refinery. The analysis of the sulphate contents of these plants were used as bioindicators for monitoring SO2 concentration levels in and around the refinery. The results of this study showed that the three different plant species responsed differently to SO2 in terms of their sulphate contents. Generally, all three species were found to be sensitive to SO2 exposure. Furthermore, the concentration of sulphate was found to be much higher closer to the refinery. On the basis of this study, it can be stated that even though SO2 levels were lower than the permissible limit values, the sulphate contents accumulated in the plants were likely to cause plant injury especially in the vicinity of the source. This suggests that the present environmental guidelines for SO2 may not protect sensitive plant species. PMID:15244337

Abdul-Wahab, Sabah A; Yaghi, Basma

2004-01-01

282

Joint Action of O3 and SO2 in Modifying Plant Gas Exchange 1  

PubMed Central

The joint action of O3 and SO2 stress on plants was investigated by determining the quantitative relationship between air pollutant fluxes and effects on stomatal conductance. Gas exchange measurements of O3, SO2, and H2O vapor were made for Pisum sativum L. (garden pea). Plants were grown under controlled environments, and O3, SO2, and H2O vapor fluxes were evaluated with a whole-plant gas exchange chamber using the mass-balance approach. Maximum O3 and SO2 fluxes per unit area (2 sided) into leaves averaged 8 nanomoles per square meter per second with exposure to either O3 or SO2 at 0.1 microliters per liter. Internal fluxes of either O3 or SO2 were reduced by up to 50% during exposure to combined versus individual pollutants; the greatest reduction occurred with simultaneous versus sequential combinations of the pollutants. Stomatal conductance to H2O was substantially altered by the pollutant exposures, with O3 molecules twice as effective as SO2 molecules in inducing stomatal closure. Stomatal conductance was related to the integrated dose of pollutants. The regression equations relating integrated dose to stomatal conductance were similar with O3 alone, O3 plus added SO2, and O3 plus SO2 simultaneously; i.e. a dose of 100 micromoles per square meter produced a 39 to 45% reduction in conductance over nonexposed plants. With SO2 alone, or SO2 plus added O3, a dose of 100 micromoles per square meter produced a 20 to 25% reduction in conductance. When O3 was present at the start of the exposure, then stomatal response resembled that for O3 more than the response for SO2. This study indicated that stomatal responses with combinations of O3 and SO2 are not dependent solely on the integrated dose of pollutants, but suggests that a metabolic synergistic effect exists.

Olszyk, David M.; Tingey, David T.

1986-01-01

283

Fire at Iraqi sulfur plant emits SO2 clouds detected by Earth Probe TOMS  

NASA Astrophysics Data System (ADS)

A fire started at the Al-Mishraq State Sulfur plant near Mosul, Iraq on 24 June 2003 and burned for almost a month. Combustion of elemental sulfur in the fire produced dense clouds of sulfur dioxide (SO2) that were detected from space by the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) on 18 days. Estimated daily SO2 production from the continuously emitting source closely mirrors contemporaneous thermal infrared radiance from the fire sensed in the 3.96 ?m band of the Moderate Resolution Imaging Spectroradiometer (MODIS). We calculate total SO2 production during the blaze amounting to ~600 kilotons, which is roughly commensurate with the predicted SO2 yield from the inventory of elemental sulfur allegedly destroyed by the fire when potential SO2 losses are considered. This event is the largest non-volcanic SO2 emission incident measured to date by any TOMS instrument.

Carn, S. A.; Krueger, A. J.; Krotkov, N. A.; Gray, M. A.

2004-10-01

284

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

285

Horizontal and Vertical Distributions of SO2 Observed During the PEACE Missions  

Microsoft Academic Search

Measurements of sulfur dioxide (SO2) were made by a significantly modified pulsed-fluorescence analyzer during the PEACE (Pacific Exploration of Asian Continental Emission) B aircraft missions, which were conducted over the East Asian Pacific rim\\/Western Pacific region in spring 2002. The SO2 data are successfully obtained up to approximately 5 km during the whole flights. The mixing ratios of SO2 show

H. Tanimoto; S. Hatakeyama; A. Takami; K. Kita

2002-01-01

286

Designation of acid rain and SO2 control zones and control policies in China  

Microsoft Academic Search

China has become the largest producer of SO2 emissions in the world. Thus effective SO2 emission and acid rain controls are urgently needed. This paper designated the priority control zones for both SO2 emission and acid precipitation in China. The Control Zones were identified as an area of 1.09xl0 km, about 11.4% of the China's territory and about 14 Million

Jiming Hao; Shuxiao Wang; Bingjiang Liu; Kebin He

2000-01-01

287

Atmospheric SO2 Pollution and Acidity of Rain in Changchun China  

Microsoft Academic Search

It is mainly SO2 that bring about acid rain in China. Changchun City, which is located in Northeast China, is a typical city that is polluted by SO2 from coal combustion in winter. In winter, the daily mean concentration of atmospheric SO2 is about 0.10mg\\/m3 and about 5 times as high as in summer, and the daily highest concentration usually

Dexuan Wang; Wei Deng

2001-01-01

288

Formation of sulfite-like species on Cr 2O 3 after SO 2 chemisorption  

Microsoft Academic Search

The adsorption of sulfur dioxide (SO2) on polycrystalline Cr2O3 was experimentally investigated using temperature-programmed desorption (TPD). The chemisorption of SO2 on the (0001) surface was also studied using theoretical methods. Different adsorption geometries were explored for SO2 adsorption on the ?-Cr2O3 (0001) surface. Two similar adsorption configurations were found to be the most stable with chemisorption energies of ?3.09 and

V. A. Ranea; S. N. Hernandez; S. Medina; I. M. Irurzun; I. D. Coria; E. E. Mola

2011-01-01

289

Dispersion and Lifetime of the SO2 Cloud from the August 2008 Kasatochi Eruption  

NASA Technical Reports Server (NTRS)

Hemispherical dispersion of the SO2 cloud from the August 2008 Kasatochi eruption is analyzed using satellite data from the Ozone Monitoring Instrument (OMI) and the Goddard Trajectory Model (GTM). The operational OMI retrievals underestimate the total SO2 mass by 20-30% on 8-11 August, as compared with more accurate offline Extended Iterative Spectral Fit (EISF) retrievals, but the error decreases with time due to plume dispersion and a drop in peak SO2 column densities. The GTM runs were initialized with and compared to the operational OMI SO2 data during early plume dispersion to constrain SO2 plume heights and eruption times. The most probable SO2 heights during initial dispersion are estimated to be 10-12 km, in agreement with direct height retrievals using EISF algorithm and IR measurements. Using these height constraints a forward GTM run was initialized on 11 August to compare with the month-long Kasatochi SO2 cloud dispersion patterns. Predicted volcanic cloud locations generally agree with OMI observations, although some discrepancies were observed. Operational OMI SO2 burdens were refined using GTM-predicted mass-weighted probability density height distributions. The total refined SO2 mass was integrated over the Northern Hemisphere to place empirical constraints on the SO2 chemical decay rate. The resulting lower limit of the Kasatochi SO2 e-folding time is approx.8-9 days. Extrapolation of the exponential decay back in time yields an initial erupted SO2 mass of approx.2.2 Tg on 8 August, twice as much as the measured mass on that day.

Krotkov, N. A.; Schoeberl, M. R.; Morris, G. A.; Carn, S.; Yang, K.

2010-01-01

290

Electrochemical sensor monitoring of volcanic gases  

NASA Astrophysics Data System (ADS)

Advances in instrumentation have fuelled a recent growth of interest in using portable sensor systems for environmental monitoring of pollution. Developments in wireless technology are enabling such systems to operate remotely and autonomously, generating a wealth of environmental data. We report here on the application of miniature Alphasense electrochemical sensors to the detection and characterisation of gases in volcanic plumes. A highly portable sensor system was developed to operate an array of 6 low cost electrochemical sensors to detect CO, H2, HCl, SO2, H2S and NO2 at 1 Hz. A miniature pump draws air over all sensors simultaneously (i.e. sensors arranged in parallel). The sensor output in these campaigns was logged on PDAs for real-time viewing, and later download (with a view to future data-streaming). The instrument was deployed at a number of volcanoes and was subject to extremely harsh conditions including highly acidic environments, low (Antarctic) temperatures, and transport over rough terrain. Analysis methods are demonstrated that consider calibration, cross-sensitivities of the sensors to multiple gases, differing sensor response times, temperature dependence, and background sensor drift with time. The analysis is applied to a range of plume field-measurements to extract gas concentrations ranging from 100's ppmv to sub-ppmv and to characterise the individual volcano emissions. Applications of similar sensor systems for real-time long-term monitoring of volcanic emissions (which may indicate and ultimately predict eruptive behavior), and UAV and balloon-borne plume sampling are now already being realised. This work focused on demonstrating the application of electrochemical sensors to monitoring of environmental pollution from volcanoes. Other applications for similar sensors include the near-source monitoring of industrial emissions, and of pollutant levels enhanced by traffic emissions in the urban environment.

Roberts, Tjarda; Freshwater, Ray; Oppenheimer, Clive; Saffell, John; Jones, Rod; Griffiths, Paul; Braban, Christine; Mead, Iqbal

2010-05-01

291

Retrieval of volcanic SO2 column abundance from Atmospheric Infrared Sounder data  

NASA Astrophysics Data System (ADS)

The concentrations of volcanic sulphur dioxide (SO2) in the upper troposphere and lower stratosphere are inferred using new infrared measurements made by the Atmospheric Infrared Sounder (AIRS). Column abundance of SO2 is derived using the strong SO2 absorption feature near 1362 cm-1 (?3-band). The retrieval takes into account interference from water vapor across the band. Examples from several recent volcanic eruptions are given to illustrate the technique and the retrievals are compared to contemporaneous SO2 ultraviolet measurements from the Ozone Monitoring Instrument (OMI), Global Ozone Monitoring Experiment (GOME) and Total Ozone Mapping Spectrometer (TOMS).

Prata, A. J.; Bernardo, C.

2007-10-01

292

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

293

The global distribution, abundance, and stability of SO2 on Io  

NASA Technical Reports Server (NTRS)

Voyager multispectral mosaics, earth-observed spectra, and photometric characterizations have been used to model and globally map the SO2 distribution and abundances, the bolometric hemispheric albedos, and the passive surface temperatures on Io. The SO2 is noted to be concentrated in the bright equatorial band, while being deficient in the region defined by Pele-type volcanic eruptions and the polar regions. The brightest, locally coldest areas correspond to SO2-rich regions, although many small patches occur elsewhere. These results are found to support the regional cold-trapping model for the surface and atmospheric SO2 of Fanale et al. (1982).

Mcewen, Alfred S.; Soderblom, Laurence A.; Johnson, Torrence V.; Matson, Dennis L.

1988-01-01

294

[Effects of gaseous compositions the on simultaneous removal of NO(x) and SO2 from simulated flue gas by ammonia absorption].  

PubMed

The effects of NO(x) oxidation ratio, O2 and SO2 concentrations in simulated flue gas as well as addition of S(IV) oxidation inhibitor NaS2O3 on the simultaneous removal of SO2 and NO(x) by ammonia absorption were investigated under the conditions of pH 5.9-6.1 and aqueous S(IV) concentration > or = 1.0 mol x L(-1). The research results showed that NO2 could be effectively absorbed by ammonium sulfite, but the NO absorption was negligible. Therefore, NO oxidation is the premise of NO(x) removal. Aqueous S(IV) concentration is a key factor affecting NO2 absorption removal, the higher the O2 concentration or the lower the SO2 concentration, the faster the aaqueous S(IV) concentration decreased, which resulted in a faster decrease of NO2 removal efficiency. S(IV) oxidation was inhibited to some extent by the addition of oxidation inhibitor S2O3(2-) into the absorption solution. As a result, the decrease of NO2 removal efficiency became slower. PMID:23487913

Wang, Hong; Zhu, Tian-Le; Wang, Mei-Yan

2013-01-01

295

Dissociation dynamics of the methylsulfonyl radical and its photolytic precursor CH3SO2Cl.  

PubMed

The dissociation dynamics of methylsulfonyl radicals generated from the photodissociation of CH(3)SO(2)Cl at 193 nm is investigated by measuring product velocities in a crossed laser-molecular beam scattering apparatus. The data evidence three primary photodissociation channels of the precursor: S-Cl fission to produce Cl atoms and ground electronic state CH(3)SO(2) radicals, S-Cl fission to produce Cl atoms and electronically excited CH(3)SO(2) radicals, and S-CH(3) fission. Some of the vibrationally excited CH(3)SO(2) radicals undergo subsequent dissociation to CH(3) + SO(2), as do all of the electronically excited radicals. The velocities of the SO(2) products show that the vibrationally excited ground state CH(3)SO(2) radicals dissociate via a loose transition state having a small exit barrier beyond the endoergicity. Hence, a statistical recoil kinetic energy distribution should and does fit the distribution of velocities imparted to these SO(2) products. The electronically excited CH(3)SO(2) radicals also dissociate to CH(3) + SO(2), but with a larger average release to relative kinetic energy. Interestingly, when using 200 eV electron bombardment detection, the ground electronic state CH(3)SO(2) radicals having too little internal energy to dissociate are not observed at the parent CH(3)SO(2)(+) ion, but only at the CH(3)(+) daughter ion. They are distinguished by virtue of the velocity imparted in the original photolytic step; the detected velocities of the stable radicals are consistent with the calculated barrier of 14.6 kcal/mol for the dissociation of CH(3)SO(2) to CH(3) + SO(2). We present CCSD(T) calculations of the adiabatic excitation energy to the lowest excited state of CH(3)SO(2) radicals, the 1 (2)A(") state, as well as the vertical energy from the equilibrium geometry of that excited state to the 2 (2)A(") state, to aid in the experimental assignment. PMID:19655865

Alligood, Bridget W; FitzPatrick, Benjamin L; Glassman, Emily Jane; Butler, Laurie J; Lau, Kai-Chung

2009-07-28

296

Total cross sections of electron scattering by several sulfur-containing molecules OCS, SO2, SF4, SF6, SF5CF3, SO2Cl2 and SO2ClF at 30-5000 eV  

NASA Astrophysics Data System (ADS)

Total cross sections of electron scattering by several sulfur-containing molecules OCS, SO{2}, SF{4}, SF{6}, SF{5}CF{3}, SO{2}Cl{2} and SO{2}ClF are calculated at the Hartree-Fork level employing the modified additivity rule approach. The modified additivity rule approach, which was proposed by Shi et al. [Eur. Phys. J. D 45, 253 (2007); Nucl. Instrum. Meth. B 254, 205 (2007)], takes into consideration that the contributions of the geometric shielding effect vary as the energy of incident electrons, the target's molecular dimension and the atomic and electronic numbers in the molecule. The present investigations cover the impact energies ranging from 30 to 5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories. Good agreement is observed even at energies of several tens of eV. It shows that the modified additivity rule approach is applicable to carry out the total cross section calculations of electron scattering by these sulfur-containing molecules at intermediate and high energies, especially over the energy range above 100 eV or so. In the present calculations, the atoms are still represented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption terms.

Shi, D. H.; Sun, J. F.; Liu, Y. F.; Zhu, Z. L.; Ma, H.

2009-07-01

297

Sorption of SO2 and Regeneration of Alkalized Alumina in Fluidized-Bed Reactors.  

National Technical Information Service (NTIS)

Two fluidized-bed reactors were designed, built, and operated, one as a sorber for SO2 and the other as a contactor for the regeneration of the sulfur-laden alkalized alumina (NaAlO2). The target of 90 percent removal of SO2 from a flue gas stream contain...

J. I. Paige J. W. Town J. H. Russell H. J. Kelly

1970-01-01

298

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...

299

INTERSPECFIC VARIATION IN SO2 FLUX - LEAF SURFACE 'VERSUS' INTERNAL FLUX, AND COMPONENTS OF LEAF CONDUCTANCE  

EPA Science Inventory

The object of the 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...

300

Modeling of SO2 Removal in Spray-Dryer Flue-Gas Desulfurization System.  

National Technical Information Service (NTIS)

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 correspond...

A. S. Damle

1985-01-01

301

SO2-promoted catalytic N2O removal over iron zeolites.  

PubMed

SO(2) promotes the rate of N(2)O removal over Fe-zeolites more efficiently than other reducing agents (NH(3)) and promoters (NO); the effect of SO(2) as selective reductant is independent of the framework type and composition, preparation method, and iron content, suggesting that its occurrence is not determined by a highly specific iron speciation. PMID:18985207

Pérez-Ramírez, Javier; Hevia, Miguel A G; Abelló, Sònia

2008-11-14

302

Investigation of Lithium Sulfur Dioxide (Li/SO2) Battery Safety Hazards -- Chemical Studies.  

National Technical Information Service (NTIS)

The chemistry associated with the discharge and forced overdischarge of the Li/SO2 cell was investigated in detail. A procedure for the quantitative determination of Li2S2O4 in discharged Li/SO2 cells is described. The amount of Li2S2O4 found in cells dis...

K. M. Abraham M. W. Rupich L. Pitts

1982-01-01

303

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...

304

Optimal SO2 compliance planning using probabilistic production costing and generalized benders decomposition  

Microsoft Academic Search

In 1990, the US Congress passed a new Clean Air Act which contains provisions to control sulfur dioxide (SO2 a primary cause of acid rain) emitted from electric generation plants in the United States. Under this Act, electric utilities will be able to choose from a wide range of SO2 emissions control measures. This paper presents a comprehensive emissions control

Wenxiong Huang; Benjamin F. Hobbs

1994-01-01

305

Amelioration of SO2 stress under fertilizer regime in a vegetable crop  

Microsoft Academic Search

Urea, superphosphate and potash fertilizers have been used as a nitrogen (N), phosphorus (P) and potassium (K) source of mineral nutrients to recover the SO2 stress in three varieties: Parbhani Kranti, Anamika and Pusa Sawani of a common vegetable crop, A. esculentus (L.). Thirty?day SO2 exposed crop has been treated with recommended dose of fertilizers individually and in combination. Leaves

V. KATIYAR; P. S. DUBEY

2005-01-01

306

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...

307

76 FR 19661 - Response to Petition From New Jersey Regarding SO2  

Federal Register 2010, 2011, 2012, 2013

...40 CFR Part 52 Response to Petition From New Jersey Regarding SO 2 Emissions From...RIN 2060-AQ69 Response to Petition From New Jersey Regarding SO 2 Emissions From...ambient air quality standard (NAAQS) in New Jersey. This finding is proposed in...

2011-04-07

308

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...

309

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...

310

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,...

311

Accurate measurement of volcanic SO2 flux: Determination of plume transport speed and integrated SO2 concentration with a single device  

Microsoft Academic Search

Ground-based measurements of volcanic sulfur dioxide fluxes are important indicators of volcanic activity, with application in hazard assessment, and understanding the impacts of volcanic emissions upon the environment and climate. These data are obtained by making traverses underneath the volcanic plume a few kilometers from source with an ultraviolet spectrometer, measuring integrated SO2 concentrations across the plume's cross section, and

A. J. S. McGonigle; S. Inguaggiato; A. Aiuppa; A. R. Hayes; C. Oppenheimer

2005-01-01

312

Determination of SO(2) in Wines Using a Flow Injection Analysis System with Potentiometric Detection.  

PubMed

This paper describes the development and application of a flow injection analysis system manifold comprising a gas diffusion unit and a potentiometric detector to the determination of free and total SO(2) in white and red wines. A homogeneous crystalline iodide double-membrane tubular electrode was used as detector. SO(2) determination based on the Ripper method was carried out by dosing the iodide formed in the oxidation of SO(2) with iodine, followed by the separation of the formed compound through a diffusion Teflon membrane. The results obtained from the analyses of free and total SO(2) in 30 wine samples showed good agreement between the proposed method and the rapid assay method recommended by the UE and OIV. The relative error deviations of the results obtained by both methods were <6%. This procedure is suitable for samples with approximately 3.2-180 mg L(-)(1) SO(2), performing determinations of 75-100 samples h(-)(1). PMID:10554214

Araújo; Couto; Lima; Montenegro

1998-01-19

313

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

314

Spatiotemporal variations of tropospheric SO2 over China by SCIAMACHY observations during 2004-2009  

NASA Astrophysics Data System (ADS)

This paper presents results of measurements of tropospheric sulphur dioxide (SO2) from satellite over China during 2004-2009. SCIAMACHY/ENVISAT SO2 data products have been validated by ground based remote sensing instrument MAXDOAS in China, and with predictions of the atmospheric model GEOS-Chem. The spatial and temporal distribution of tropospheric SO2 over China is discussed in this study. The result shows that the SO2 load over East China is decreasing since strong control for pollution emission in 2007 for preparation of 2008 Olympic Games in China, while the SO2 load in West China is increasing all the way during 2004-2009, which might reflect that the anthropogenic activity was added to promote the economy development in west of China. Typical seasonal variation with high pollution levels in winter and low in summer is found in the northwest of China, while the inverse seasonal variation is found for the south of China. The characteristics of tropospheric SO2 over the major cities in China were explored and found that tropospheric SO2 was partly under control from 2007 because of the policy from China government for reduction in SO2 emissions in 2006. And the SO2 value shows remarkably decrease in most of the major cities after 2007 because strong control for the pollution emission for 2008 Olympic games. Guangzhou city shows high SO2 pollution levels in summer time, since most of the coal power plants and thermal power industry are located to the south of Guangzhou city and southerly winds dominate during summer time.

Zhang, Xingying; van Geffen, Jos; Liao, Hong; Zhang, Peng; Lou, Sijia

2012-12-01

315

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

316

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 (39.77°N, 117.0°E) located at ~50 km South-East 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 to correlative measurements from in situ instruments, as well as meteorological data. A marked seasonality is 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 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 parameters in controlling the level of the SO2-related pollution at Xianghe. In the case of east or southwest wind, the SO2 concentration rises with the increase of the wind speed, since heavy polluting industries are located to the east and southwest of the station. In contrast, when wind comes from other directions, the stronger the wind, the less SO2 is observed. 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. 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, demonstrating the reliability and robustness of our retrieval.

Wang, Ting; Hendrick, Francois; Wang, Pucai; Tang, Guiqian; Clémer, Katrijn; Yu, Huan; Fayt, Caroline; Hermans, Christian; Gielen, Clio; Pinardi, Gaia; Theys, Nicolas; Brenot, Hugues; Van Roozendael, Michel

2014-05-01

317

SO2 over Central China: Measurements, Numerical Simulations and the Tropospheric Sulfur Budget  

NASA Technical Reports Server (NTRS)

SO2 in central China was measured in situ from an aircraft and remotely using the Ozone Monitoring Instrument (OMI) from the Aura satellite; results were used to develop a numerical tool for evaluating the tropospheric sulfur budget - sources, sinks, transformation and transport. In April 2008, measured ambient SO2 concentrations decreased from approx.7 ppbv near the surface to approx. 1 ppbv at 1800 m altitude (an effective scale height of approx.800 m), but distinct SO2 plumes were observed between 1800 and 4500 m, the aircraft's ceiling. These free tropospheric plumes play a major role in the export of SO2 and in the accuracy of OMI retrievals. The mean SO2 column contents from aircraft measurements (0.73 DU, Dobson Units) and operational OMI SO2 products (0.63+/-0.26 DU) were close. The OMI retrievals were well correlated with in situ measurements (r = 0.84), but showed low bias (slope = 0.54). A new OMI retrieval algorithm was tested and showed improved agreement and bias (r = 0.87, slope = 0.86). The Community Multiscale Air Quality (CMAQ) model was used to simulate sulfur chemistry, exhibiting reasonable agreement (r = 0.62, slope = 1.33) with in situ SO2 columns. The mean CMAQ SO2 loading over central and eastern China was 54 kT, approx.30% more than the estimate from OMI SO2 products, 42 kT. These numerical simulations, constrained by observations, indicate that ",50% (35 to 61 %) of the anthropogenic sulfur emissions were transported downwind, and the overall lifetime of tropospheric SO2 was 38+/-7 h.

He, Hao; Li, Can; Loughner, Christopher P.; Li, Zhangqing; Krotkov, Nickolay A.; Yang, Kai; Wang, Lei; Zheng, Youfei; Bao, Xiangdong; Zhao, Guoqiang; Dickerson, Russell R.

2012-01-01

318

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 studentsâ 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.

319

Noble Gases  

NASA Astrophysics Data System (ADS)

The noble gases are the group of elements - helium, neon, argon, krypton, xenon - in the rightmost column of the periodic table of the elements, those which have "filled" outermost shells of electrons (two for helium, eight for the others). This configuration of electrons results in a neutral atom that has relatively low electron affinity and relatively high ionization energy. In consequence, in most natural circumstances these elements do not form chemical compounds, whence they are called "noble." Similarly, much more so than other elements in most circumstances, they partition strongly into a gas phase (as monatomic gas), so that they are called the "noble gases" (also, "inert gases"). (It should be noted, of course, that there is a sixth noble gas, radon, but all isotopes of radon are radioactive, with maximum half-life a few days, so that radon occurs in nature only because of recent production in the U-Th decay chains. The factors that govern the distribution of radon isotopes are thus quite different from those for the five gases cited. There are interesting stories about radon, but they are very different from those about the first five noble gases, and are thus outside the scope of this chapter.)In the nuclear fires in which the elements are forged, the creation and destruction of a given nuclear species depends on its nuclear properties, not on whether it will have a filled outermost shell when things cool off and nuclei begin to gather electrons. The numerology of nuclear physics is different from that of chemistry, so that in the cosmos at large there is nothing systematically special about the abundances of the noble gases as compared to other elements. We live in a very nonrepresentative part of the cosmos, however. As is discussed elsewhere in this volume, the outstanding generalization about the geo-/cosmochemistry of the terrestrial planets is that at some point thermodynamic conditions dictated phase separation of solids from gases, and that the Earth and the rest of the inner solar were made by collecting the solids, to the rather efficient exclusion of the gases. In this grand separation the noble gases, because they are noble, were partitioned strongly into the gas phase. The resultant generalization is that the noble gases are very scarce in the materials of the inner solar system, whence their common synonym "rare gases."This scarcity is probably the most important single feature to remember about noble-gas cosmochemistry. As illustration of the absolute quantities, for example, a meteorite that contains xenon at a concentration of order 10 -10 cm3STP g -1 (4×10-15 mol g-1) would be considered relatively rich in xenon. Yet this is only 0.6 ppt (part per trillion, fractional abundance 10-12) by mass. In most circumstances, an element would be considered efficiently excluded from some sample if its abundance, relative to cosmic proportions to some convenient reference element, were depleted by "several" orders of magnitude. But a noble gas would be considered to be present in quite high concentration if it were depleted by only four or five orders of magnitude (in the example above, 10-10 cm3STP g-1 of xenon corresponds to depletion by seven orders of magnitude), and one not uncommonly encounters noble-gas depletion of more than 10 orders of magnitude.The second most important feature to note about noble-gas cosmochemistry is that while a good deal of the attention given to noble gases really is about chemistry, traditionally a good deal of attention is also devoted to nuclear phenomena, much more so than for most other elements. This feature is a corollary of the first feature noted above, namely scarcity. A variety of nuclear transmutation processes - decay of natural radionuclides and energetic particle reactions - lead to the production of new nuclei that are often new elements. Most commonly, the quantity of new nuclei originating in nuclear transmutation is very small compared to the quantity already present in the sample in question,

Podosek, F. A.

2003-12-01

320

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

321

Studies of proton-irradiated SO2 at low temperatures Implications for Io  

NASA Astrophysics Data System (ADS)

The infrared absorption spectrum from 3.3 to 27 microns of SO2 ice films has been measured at 20 and 88 K before and after 1-MeV proton irradiation. The radiation flux was chosen to simulate the estimated flux of Jovian magnetospheric 1-MeV protons incident on Io. After irradiation, SO3 is identified as the dominant molecule synthesized in the SO2 ice. This is also the case after irradiation of composite samples of SO2 with sulfur or disulfites. Darkening was observed in irradiated SO2 ice and in irradiated S8 pellets. Photometric and spectral measurements of the thermoluminescence of irradiated SO2 have been made during warming. The spectrum appears as a broad band with a maximum at 4450 A. Analysis of the luminescence data suggests that at Ionian temperatures irradiated SO2 ice would not be a dominant contributor to posteclipse brightening phenomena. After warming to room temperature, a form of SO3 remains along with a sulfate and S8. Based on these experiments, it is reasonable to propose that small amounts of SO3 may exist on the surface of Io as a result of irradiation synthesis in SO2 frosts.

Moore, M. H.

1984-07-01

322

SO2 removal with coal slurry in a double-stirred vessel.  

PubMed

In the coal slurry scrubbing process, SO2 can be removed through both the coal pyrite leaching reaction and the oxidation reactions catalysed by Fe2+/Fe3+ produced in situ. In the present study, experiments of SO2 removal with coal slurry (particle size fraction 65-150 microm) were carried out using a double-stirred vessel to investigate the effects of temperature, coal particle size and pulp density on SO2 absorption rate and on the proportion of SO2 removed through the leaching reaction. Results show that the SO2 absorption rate can be increased by decreasing particle size and increasing pulp density, but it is relatively less affected by temperature. Although decreasing coal particle size and pulp density can increase coal pyrite conversion, the effectiveness is limited and the proportion of SO2 removed through the leaching reaction is little affected. Increasing temperature can evidently increase the proportion, but there also exists the problem of energy expenditure; satisfactory coal pyrite conversion during SO2 removal could not be achieved economically by such measures. In addition, the apparent rate constant has a linear relationship with the reciprocal of the coal particle diameter. PMID:24527610

Sun, Wenshou; Wang, Liang; Liu, Jingchun; Wang, Lichao; Zhang, Ying

2013-01-01

323

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

324

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

325

Measurements of aerosol and trace gases at Agra in Indo-Gangetic plain during special aerosol land campaign II  

NASA Astrophysics Data System (ADS)

This paper deals with measurements of aerosol, their chemical properties and precursor trace gases at Agra in the Indo-Gangetic plain during ISRO-GBP special aerosol land campaign II. Aerosol and trace gas sampling as well a meteorological parameters monitoring were carried out at Dayalbagh, a suburban site of Agra during campaign in December 2004 along with seven other stations in India. The average TSPM level was 441.2 µg m-3 and ranges between 60.8 µg m-3 and 1004.6 µg m-3 and was higher than National Ambient Air Quality Standard values of India. The high load SPM in this region may be probably due to industrial-vehicular emissions of sulphur and nitrogen oxides, transport of soil-sand dust from local agricultural field and Thar Desert of Rajasthan and long range transported pollutants. Meteorological study revealed that high wind speed and wind from North West direction influences the aerosol load as it may be long range transported. TSP load was higher during initial foggy and foggy days and lower during post foggy days. NH4+ concentration is highest followed by NO3-, SO42-, Cl-, K+, Ca2+, Na+, Mg2+ and F-. The high concentration of NH4+ may be probably due to nearby cattle yard, use of fertilizers and biogenic emissions. The concentration of trace gases SO2, NO2, HNO3 and NH3 are 20.8 µg m-3, 26.3 µg m-3, 1.6 µg m-3, 18.6 µg m-3, respectively. The transportation of urban plumes may be responsible for high concentration of SO2 and NO2. HNO3/NO3- ratio is less than unity. NO3- and NO2 (r=0.4) suggests formation of particulate NO3- from NO2. Ratio of NH3/NH4+ is less than unity. SO42-/SO2 ratio is 0.84. The lack of correlation between SO42- and SO2 (r = 0.14) indicates only a small fraction of SO42- is contributed by SO2 while the major fraction is contributed by soil and other sources probably long range transported sulphate.

Kumar, Ranjit; Maharaj Kumari, K.

2010-05-01

326

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

327

The Galileo probe Li/SO2 battery: The safest battery on Jupiter  

NASA Technical Reports Server (NTRS)

The unique power requirement of NASA's Galileo Jupiter Probe are most readily met by a Li/SO2 battery; however, because this battery system is not space flight proven, extensive effort was required to qualify this device from the stand point of performance and safety. Due to the rather checkered safety record of the Li/SO2 system, safety has been foremost among the design considerations and has been addressed at the cell, battery and system level. The mission requirements which led to the choice of the Li/SO2 battery and the safety engineering which went into the battery and power system design are described.

Marcoux, L. S.; Dagarin, B. P.

1983-01-01

328

The global distribution, abundance, and stability of SO2 on Io  

USGS Publications Warehouse

Sulfur dioxide distribution and abundances, bolometric hemispheric albedos, and passive surface temperatures on Io are modeled and mapped globally from Voyager multispectral mosaics, Earth-based spectra, and photometric descriptions. Photometric models indicate global average values for regolith porosity of 75-95% and macroscopic roughness with a mean slope angle of ~30??. Abundances of SO2 suggested by observations at uv-visible wavelengths and at 4.08 ??m are partially reconciled by intimate-mixing models; 30-50% SO2 coverage of the integral disk is indicated. Three major spectral end members, with continuous mixing, are recognized from the Voyager multispectral mosaics; one of these end members is identified as SO2. Intimate-mixing models with the three spectal end members are used to produce abundance maps for the optical surface; ~30% of Io's total optical surface consists of SO2. The SO2 is concentrated in the bright equatorial band and is relatively deficient in the region of Pele-type volcanic reuptions (long 240??-360??) and the polar regions. Temperatures are computed to vary over a 40??K range, at the same illumination angle, according to variations in surface bolometric hemispheric albedo. The brightest (and locally coldest) areas correspond to areas rich in SO2 and are concentrated in an equatorial band (??30?? lat), but many small cold patches occur elsewhere. These cold patches have radiative equilibrium temperatures ???120??K at the subsolar point, resulting in SO2 saturation vapor pressures ???10-8 bar. Midlatitude areas and the region of Pele-type plume eruptions are generally warmer (due to lower albedos). These results for surface temperatures and SO2 abundances and distribution support the regional coldtrapping model for the surface and atmospheric SO2 presented by F.P. Fanale, W.B. Banerdt, L.S. Elson, T.V. Johnson, and R.W. Zurek (1982, In Satellites of Jupiter (D. Morrison, Ed.), pp. 756-781, Univ. of Arizona Press, Tucson), although the region of Pele-type volcanic eruptions may be better characterized by the regolith condtrapping/volcanic-venting model of D.L. Matson and D.B. Nash (1983, J. Geophys. Res. 88, 4771-4783). The bright equatorial band is especially effective at slowing the formation of polar caps of SO2, both by reducing the sublimation rate near the subsolar point and by coldtrapping the SO2 in the equatorial region, so that competing processes of sputtering and volcanic resurfacing may prevent the formation of polar SO2 caps.

McEwen, A. S.; Johnson, T. V.; Matson, D. L.; Soderblom, L. A.

1988-01-01

329

SO2 emissions from paroxysmal eruptions at Etna volcano in 2011-12  

NASA Astrophysics Data System (ADS)

Mt Etna's activity has increased during the last decade with a tendency towards more explosive eruptions that produce paroxysmal lava fountains. From January 2011 to April 2012, 25 lava fountaining episodes took place at Etna's New South-East Crater (NSEC). Improved understanding of the mechanism driving these explosive basaltic eruptions is needed to reduce volcanic hazards and develop models of Etna's plumbing system.. This type of activity produces high sulfur dioxide (SO2) emissions, associated with lava flows and ash fall-out, but to date the SO2 emissions associated with Etna's lava fountains have been poorly constrained. The Ultraviolet (UV) Ozone Monitoring Instrument (OMI) on NASA's Aura satellite and the Atmospheric Infrared Sounder (AIRS) on Aqua were used to measure the SO2 loadings. Ground-based data from the Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) L-band Doppler radar, VOLDORAD 2B, used in collaboration with the Italian National Institute of Geophysics and Volcanology in Catania (INGV-CT), also detected the associated ash plumes, giving precise timing and duration for the lava fountains. This study resulted in the first detailed analysis of the OMI and AIRS SO2 data for Etna's lava fountains during the 2011-2012 eruptive cycle. The HYSPLIT trajectory model is used to constrain the altitude of the observed SO2 clouds, and results show that the SO2 emission usually coincided with the lava fountain peak intensity as detected by VOLDORAD. The UV OMI and IR AIRS SO2 retrievals permit quantification of the SO2 loss rate in the volcanic SO2 clouds, many of which were tracked for several days after emission. Using SO2 loadings corrected for the time of emission, we observe a correlation between SO2 production and inter-paroxysm repose time, suggesting that gas accumulation drives the paroxysms. We therefore suggest that our data set supports the collapsing foam (CF) model [Parfitt (2004) J. Volcanol. Geotherm. Res. 134, 77-107.] as the driving mechanism for the paroxysmal events at the NSEC. Using VOLDORAD-based estimates of the erupted magma mass, we observe a large excess of SO2 in the eruption clouds, confirming the gas-rich composition of the lava fountains.

Bonny, E.; Mandon, C.; Carn, S. A.; Prata, F.; Coltelli, M.; Donnadieu, F.

2013-12-01

330

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

331

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

332

Phase equilibriums, ion association, and mechanisms of solvation in the LiN(CF3SO2)2-(CH3)2SO2 system  

NASA Astrophysics Data System (ADS)

The phase diagrams, isotherms of the electrical conductivity, Raman spectra, and time correlation functions of vibrational dephasing are studied for the LiN(CF3SO2)2-(CH3)2SO2 system, which is promising for use as an electrolyte in medium-temperature lithium-ion batteries. The phase diagram of this system contains a broad supercooled region. It is shown that the concentration dependences of the electrical conductivity are typical for solutions of strong electrolytes. The Raman spectra and the time correlation functions of vibrational dephasing for the anion and the solvent indicate that in the supercooling range, cations are weakly solvated by solvent molecules and form ion pairs.

Gafurov, M. M.; Rabadanov, K. Sh.; Prisyazhnyi, V. D.; Tret'yakov, D. O.; Gorobets, M. I.; Kirillov, S. A.; Ataev, M. B.; Kakagasanov, M. M.

2011-09-01

333

Light-induced Light Emission (DLE) as an Indictor of Artificial Acid Rain and SO2  

Microsoft Academic Search

Effects of artificial acid rain and SO2 on characteristics of DLE were studied. Results reveal that the changes in DLE intensity may provide a new approach for the detection of environmental pollution.

Chenglong Wang; Duowang Fan; Da Xing; Hai Sun; Hongzhong Liu

2007-01-01

334

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

NASA Astrophysics Data System (ADS)

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 ?m for SO2 and SO3, respectively, with a common dual-beam detection system. We inferred a noise-equivalent absorbance of ˜1×10-4 Hz-1/2. We have demonstrated detection limits for both SO2 and SO3 of 1 2 ppmv m/Hz1/2 (where ppmv is parts in 106 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.

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

2005-11-01

335

Identification of Regenerable Metal Oxide SO2 Sorbents for Fluidized-Bed Coal Combustion.  

National Technical Information Service (NTIS)

The report briefly summarizes results of an analysis to identify regenerable metal oxide SO2 sorbents for fluidized-bed coal combustion. It recommends continued investigation. It discusses both the approach used for the theoretical study of sorption/regen...

P. S. Lowell T. B. Parsons

1975-01-01

336

Assessment of SO2 and NOx Emission Control Technology in Europe.  

National Technical Information Service (NTIS)

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 cataly...

W. Ellison

1988-01-01

337

Regeneration of Calcium-Based SO2 Sorbents for Fluidized-Bed Combustion: Engineering Evaluation.  

National Technical Information Service (NTIS)

The report gives results of an engineering evaluation of regeneration of calcium-based SO2 sorbents (limestone and dolomite) for application in both atmospheric and pressurized fluidized-bed combustion (FBC) processes. Economics of FBC power plants, opera...

R. A. Newby S. Katta D. L. Keairns

1978-01-01

338

Wall-Fired Boiler Design Criteria for Dry Sorbent SO2 Control with Low NOx Burners.  

National Technical Information Service (NTIS)

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 conjun...

R. K. Mongeon

1987-01-01

339

Measurements of volcanic SO2 with ASTER. Comparison with automated scanning DOAS measurements  

NASA Astrophysics Data System (ADS)

Sulfur dioxide (SO2) emitted by volcanoes has an important impact on the environment and climate and is also a critical parameter for volcano monitoring. A number of satellites operating in the ultra violet and in the Thermal infrared can measure SO2. However a lot of work has still to be done towards a rigorous validation of SO2 measurements from space. ASTER (Advanced Spaceborne Thermal Emission Reflection radiometer) acquires images in the thermal infrared (TIR) with a resolution of 90m/pixel, which enables to quantify the SO2 fluxes emitted in small-scale tropospheric plumes. ASTER images are processed with radiative transfer simulations and a band ratio algorithm to produce maps of SO2 column amounts. The band ratios (B10+B12)/B11 and B14/B11 are used for their insensitivity to variations in ground altitude and atmospheric humidity, two variables that often complicate SO2 retrievals in the TIR. Their sensitivity to surface emissivity is also reduced. So far, the ground validation of satellite SO2 measurements has been complex due to logistics difficulties and the lack of strictly simultaneous measurements. Recently the development of permanent networks of scanning DOAS on several active volcanoes has provide a wealth of ground based SO2 measurements that can be exploited for validating satellite-based measurements. We will present the results of comparisons between SO2 Column Amount (CA) and fluxes measured by ASTER and by the FLAME network of Mt. Etna. The two independent measurements sets are in good agreement in magnitude. Fluxes range from 2000 to 5000 T/days and column amounts from 0 to 4 g/m2. CAs measured by ASTER present a 0.5g/m2 random dispersion and no systematic bias compared to DOAS measurements. However the CAs measured by DOAS are subject to increase at low-scanning angles. These results constitute a rigorous ground validation of ASTER SO2, and provides valuable insights into accuracy and precision on both methodologies. Figure 1: Comparison between measurements of SO2 column amounts measured by ASTER and DOAS in the plume of Etna on 3rd August 2006.

Campion, R. A.; Salerno, G. G.; Bernard, A. M.; Burton, M.; Coheur, P.; Caltabiano, T.

2009-12-01

340

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

341

Comments on D-brane and SO(2 n) enhanced symmetry in type II string  

Microsoft Academic Search

We propose a configuration of D-branes welded by analogous orbifold operation to be responsible for the enhancement of SO(2n) gauge symmetry in type II string compactified on the Dn-type singular limit of K3. Evidences are discussed from the Dn-type ALE and D-manifold point of view. A subtlety regarding the ability of seeing the enhanced SO(2n) gauge symmetry perturbatively is briefly

H. B. Gao

1997-01-01

342

Evaluation of simultaneous SO2\\/NOx control technology. Final report, October 1990May 1993  

Microsoft Academic Search

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 boilers: injection temperature, sorbent type, and reductant\\/pollutant stoichiometric ratio. Up to 80% reduction of SO2 and NOx at reactant\\/pollutant stoichiometric ratios of 2 and 1.5, respectively,

K. R. Bruce; W. F. Hansen

1993-01-01

343

Sorbent\\/urea slurry injection for simultaneous SO2\\/NOx removal  

Microsoft Academic Search

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 and various Ca-based sorbents was injected at a range of temperatures and reactant\\/pollutant stoichiometries. Testing on a natural-gas pilot-scale reactor with doped pollutants achieved up to 80% reduction of SO2 and NOx at

Brain K. Gullett; Kevin R. Bruce; Walter F. Hansen; John E. Hofmann

1992-01-01

344

Industrial experiments on pulse corona simultaneous removal of NO x and SO2 from flue gas  

Microsoft Academic Search

The corona-induced simultaneous removal of NOx and SO 2 from flue gas is based on the application of narrow voltage pulses to an electrode structure similar to that of an electrostatic precipitator. The free electrons of the corona discharge, having energy up to 20 eV, originate active radicals which lead to the transformation of NOx and SO2 into their acids

G. Dinelli; L. Civitano; M. Rea

1990-01-01

345

Vibrational analyses of sulfamoyl halides NH 2SO 2X (X is F, Cl and Br)  

Microsoft Academic Search

The structural stability of sulfamoyl halides NH2–SO2X (X is F, Cl and Br) were investigated by DFT-B3LYP\\/6-311+G** and ab initio MP2\\/6-311+G** calculations. From the calculations the molecules were predicted to exist only in the anti (XS bond is anti with respect to nitrogen lone pair) conformation with the possibility of very low abundance of the syn (SO2 and NH2 groups

Hassan M. Badawi

2006-01-01

346

Direct sulfonation of methane to methanesulfonic acid with SO2 using Ca salts as promoters.  

PubMed

Direct liquid-phase sulfonation of methane to methanesulfonic acid (MSA) with SO2 has been achieved in triflic acid using K2S2O8 as the oxidant and a small amount of a Ca salt as the promoter. The effects of reaction conditions on the conversion of SO2 to MSA were examined. Included were the influence of solvent acidity, reaction duration, reaction temperature, amount of K2S2O8, and composition and amount of promoters. PMID:12683795

Mukhopadhyay, Sudip; Bell, Alexis T

2003-04-16

347

Reduction of SO 2 to elemental sulfur over rare earth-iron catalysts  

Microsoft Academic Search

With coal gas as a reducing agent, the catalytic reduction of SO2 to sulfur in the flue gas produced in metallurgical processes was studied over catalysts of rare earth-Fe\\/Al2O3 (REFe\\/Al2O3). The catalytic activity of the REFe\\/Al2O3 catalyst on the reduction of SO2 to sulfur was investigated based on kinds and the contents of rare earths and different preparation method of

Gengfeng DENG; Kun JIANG; Xia CAO; Chunfa LIAO

2009-01-01

348

Thermoluminescence (TL) and ESR study of ?-irradiated SO 2 frost for future dating in outer planets  

Microsoft Academic Search

Thermoluminescence (TL) and electron spin resonance (ESR) of SO2 frost were studied for future TL and ESR dating of materials from the outer planets. The solid SO2 gamma-ray-irradiated at 77 K shows five TL peaks at about 110, 125, 140, 150 and 180 K. TL curves were simulated to obtain the activation energy E and the frequency factor v0. The

K. Kanosue; H. Toda; M. Hirai; H. Kanamori; M. Ikeya

1997-01-01

349

CaO dispersed on carbon as an SO 2 sorbent  

Microsoft Academic Search

Calcium-containing carbons were tested as low-temperature sorbents for SO2. CaO particles dispersed on carbon were prepared by thermal decomposition of calcium acetate. Samples with calcium contents ranging from 1.5 to 8.0 wt% were analysed. CO2 chemisorption was used to characterize the area of the CaO particles available to interact with and retain SO2. CaO surface areas confirm that CaO dispersed

Marcia J. Muñoz-Guillena; M. C. Macías-Pérez; Angel Linares-Solano; Concepción Salinas-Martínez de Lecea

1997-01-01

350

Interaction of SO2 with clean and Cs-precovered Ag(100)  

Microsoft Academic Search

The present paper gives a first report of our investigations of the adsorption and desorption kinetics of SO2 on clean and cesiated Ag(100) by means of TPD. Deltaphi, molecular beam back scattering (MBBS) and isotope exchange experiments, assisted by AES and LEED. On clean Ag(100), SO2 is adsorbed only at temperatures Tads < 300K. Although the TPD-spectra show similarities to

M. Höfer; H. Stolz; H.-W. Wassmuth

1992-01-01

351

Gaseous deposition to snow: 2. Physical-chemical model for SO2 deposition  

NASA Astrophysics Data System (ADS)

A diffusion/reaction model of SO2 uptake by snow containing liquid water is used to examine the snowpack processes controlling accumulation of dissolved S(IV) and S(VI). Surface deposition velocity vd (defined as overall accumulation rate divided by surface SO2 concentration) depends on the amount of liquid water in the snow, the time scale considered, the rate of S(IV) to S(VI) conversion in the aqueous phase, and the SO2 concentration. In the absence of any oxidation, vd for dense snow (specific gravity 0.4) with a moderate liquid water mass fraction (Xm = 0.01) and SO2 concentration of 20 ppbv (parts per billion by volume) is calculated to be 0.026 cm s-1 after 6 hours. Deposition velocity increases by a factor of 3.2 for each tenfold increase in Xm and by a factor of 2.5-3.2 for each tenfold decrease in time. SO2 penetration into the snowpack is about 5 cm for the 6-hour case. In the presence of air containing 30 ppbv ozone and otherwise identical conditions, 80% of the accumulated sulfur is as S(VI), and the calculated vd is 0.036 cm-1. A further tenfold increase in ozone concentration gives only a 70% increase in vd. A similar dependence is calculated for oxygen (catalyzed by Fe(III)) as oxidant, but that for hydrogen peroxide is much stronger and almost linear. A tenfold increase in SO2 concentration (with ozone at 30 ppb) results in a 2.3-fold decrease in vd. Wet snow with a liquid water mass fraction of about 0.1 gives a deposition velocity at 20 ppb SO2 of 0.12 cm s-1, with a penetration of only 2 cm. Calculated and observed uptakes of SO2 by snow are in good agreement.

Bales, Roger C.; Valdez, Marc P.; Dawson, George A.

1987-08-01

352

SO2 interaction with Zn(0001) and ZnO(0001) and the influence of water  

NASA Astrophysics Data System (ADS)

Photoelectron spectroscopy has been used to study room temperature adsorption of sulfur dioxide on clean and water exposed (0001) surfaces of zinc and zinc oxide. Water has no significant effect either on clean or on SO2 exposed Zn(0001) at the low water pressures used (p < 10- 7 mbar). In the case of the zinc-terminated ZnO(0001) surface, however, water adsorbs dissociatively and OH groups are shown to have a considerable effect on SO2 surface reactions. A strong oxidation reaction occurs between Zn(0001) and SO2 giving various sulfur containing species. On ZnO(0001), SO2 interacts mainly with oxygen sites giving SO3 or SO4 species. It is shown that the ZnO(0001) sample preparation procedure can have large effects on surface chemical and physical properties. Samples cleaned by four different preparation procedures are investigated, namely sputtering only and sputtering followed by annealing at 450 °C, 530 °C and 600-650 °C. Annealing at 600 °C leads to a transition from a partly OH-terminated surface to a triangularly structured surface free from OH groups. Adsorption of SO2 on the latter surface leads to a decreased surface conductivity, which hampers photoemission measurements. Water is shown to block SO2 adsorption sites on both 450 °C and 530 °C annealed samples. On the latter sample, SO2 reduction has been observed to a small extent on the clean surface and to a larger extent when the surface is prehydroxylated. Here, we speculate that water, similar to hydrogen, generates surface zinc clusters on ZnO(0001). Zinc clusters could enable charge transfer to the antibonding LUMO of the SO2 molecule and subsequent dissociation.

Önsten, Anneli; Stoltz, Dunja; Palmgren, Pål; Yu, Shun; Claesson, Thomas; Göthelid, Mats; Karlsson, Ulf O.

2013-02-01

353

Apparent downwind depletion of volcanic SO2 flux—lessons from Masaya Volcano, Nicaragua  

NASA Astrophysics Data System (ADS)

A series of 707 measurements at Masaya in 2005, 2006, and 2007 reveals that SO2 emissions 15km downwind of the active vent appear to be ~33% to ~50% less than those measured only 5km from the vent. Measurements from this and previous studies indicate that dry deposition of sulfur from the plume and conversion of SO2 to sulfate aerosols within the plume each may amount to a maximum of 10% loss, and are not sufficient to account for the larger apparent loss measured. However, the SO2 measurement site 15km downwind is located on a ridge over which local trade winds, and the entrained plume, accelerate. Greater wind speeds cause localized dilution of the plume along the axis of propagation. The lower concentrations of SO2 measured on the ridge therefore lead to calculations of lower fluxes when calculated at the same plume speed as measurements from only 5km downwind, and is responsible for the apparent loss of SO2. Due to the importance of SO2 emission rates with respect to hazard mitigation, petrologic studies, and sulfur budget calculations, measured fluxes of SO2 must be as accurate as possible. Future campaigns to measure SO2 flux at Masaya and similar volcanoes will require individual plume speed measurements to be taken at each flux measurement site to compensate for dilution and subsequent calculation of lower fluxes. This study highlights the importance of a comprehensive understanding of a volcano’s interaction with its surroundings, especially for low, boundary layer volcanoes.

Nadeau, Patricia A.; Williams-Jones, Glyn

2009-05-01

354

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

355

Adsorption equilibrium and kinetics for SO2, NO, CO2 on zeolites FAU and LTA.  

PubMed

In order to develop a single-step process for removing SO(2), NO, CO(2) in flue gas simultaneously by co-adsorption method. Pure component adsorption equilibrium and kinetics of SO(2), NO, and CO(2) on zeolite NaY, NaX, CaA were obtained respectively. Equilibrium data were analyzed by equilibrium model and Henry's law constant. The results suggest that Adsorption affinity follows the trend SO(2)>CO(2)>NO for the same adsorbent. Zeolite with stronger polar surface is a more promising adsorbent candidate. Kinetics behavior was investigated using the breakthrough curve method. The overall mass transfer coefficient and diffusivity factor were determined by a linear driving force model. The results are indicative of micropore diffusion controlling mechanism. NaY zeolite has the minimum resistance of mass transfer duo to the wide pore distribution and large pore amount. CaA zeolite exhibits the highest spatial hindered effect. Finally, co-adsorption effect of SO(2), NO, and CO(2) were investigated by multi-components breakthrough method. SO(2) and NO may form new adsorbed species, however, CO(2) presents a fast breakthrough. Chemical adsorption causes SO(2) transforms to SO(4)(2-), however, element N and C are not detected in adsorbed zeolites. PMID:22209321

Yi, Honghong; Deng, Hua; Tang, Xiaolong; Yu, Qiongfen; Zhou, Xuan; Liu, Haiyan

2012-02-15

356

Photodissociation of SO2 as a way to cold atoms and molecules  

NASA Astrophysics Data System (ADS)

We discuss the possibility to use the photodissociation of cold SO2 molecules to produce internally and translationally cold photofragments SO and O. It is expected from our measurements of the molecular Stark effect [1] that the dissociation pathways and excess energies of the fragments are tunable by electric fields [2]. Cold SO2 molecules are produced by Stark deceleration. We have realized a Stark decelerator that is able to slow down packages SO2 in weak-field seeking levels to a few 10 m/s center of mass velocity. A Stark decelerator with 326 stages is required for this purpose, since the ratio of Stark shift to initial kinetic energy is small for SO2. The photofragments SO and O have triplet ground states, while the ground state of SO2 is diamagnetic. In combination with the photodissociation at the threshold we want to employ this constellation to accumulate fragments in a magnetic trap by dissociating SO2 as it is stopped by electric fields in the center of the trap. [1] J. Phys. B 39, S1085 (2006). [2] Phys. Rev. A 74, 040701(R) (2006).

Christian, Lisdat; Bucicov, Oleg; Nowak, Marcin; Jung, Sebastian; Tiemann, Eberhard

2008-03-01

357

SO and SO2 In The Venus Mesosphere: Observations Of Extreme And Rapid Variation  

NASA Astrophysics Data System (ADS)

Measurements of SO2 and SO in the Venus middle atmosphere (70-100 km) reveal extreme, and rapid, global variability of each molecule. Sub-mm (346 GHz) spectroscopic observations since 2004 (made with JCMT - the James Clerk Maxwell Telescope, Mauna Kea, Hawaii) indicate [SO]<<[SO2] in June 2004, [SO]>>[SO2] in Jan2007, and the total [SOx]=[SO]+[SO2] also varies strongly. In Jan2007, global SO tripled in only 6 days. SO and SO2 mixing ratios are much larger at 85-100 km than at 70-85 km. Initial measurements at higher spatial resolution indicate variability can be spatial as well as temporal. SO and SO2 measurements add to the growing body of data depicting the Venus above-cloud atmosphere as a complex and dynamic region. We discuss SOx variability in context of variability found in studies of wind and CO [see talk by Clancy], and of water [Sandor & Clancy. Icarus 177. p129. 2005.] [We acknowledge the U.S. National Science Foundation for their funding of this project.

Sandor, Brad J.; Clancy, T.; Moriarty-Schieven, G. H.

2007-10-01

358

Effect of O2 on the adsorption of SO2 on carbon-supported Pt electrocatalysts.  

PubMed

Adsorption of SO(2) in the presence of O(2) on Pt/C catalysts often used as electrocatalysts has been investigated by temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). The amounts of SO(2) adsorption on Pt/C in the presence of O(2) were much higher than those in the absence of O(2) (SO(2)-N(2)) and from the carbon support (Vulcan XC-72) alone. Adsorption is dependent on oxygen concentration over the range 0-20% but reaches saturation at 20% O(2). The spillover of SO(2) from Pt to the carbon support has been proposed for 10, 20, and 40% Pt loadings, characterized by desorption temperatures of approximately 150 and 260 °C for SO(2) adsorbed on Pt and carbon, respectively. Adsorbed Pt-S, C-S, C-SO(x), and Pt-SO(4) species were identified by XPS as S-containing species on both Pt and carbon. Both TPD and XPS indicate that the carbon support plays a major role in SO(2) adsorption, primarily as SO(x) (x = 3, 4). The bonding of S and SO(x) on the carbon support was strong enough that back diffusion to the Pt surface did not occur. PMID:21608976

Punyawudho, K; Ma, S; Van Zee, J W; Monnier, J R

2011-06-21

359

Improvements in the operation of SO2 scrubbers in China's coal power plants.  

PubMed

China has deployed the world's largest fleet of sulfur dioxide (SO(2)) scrubbers (flue gas desulfurization systems), and most of them now appear to be operating properly. Although many plant managers avoided using their SO(2) scrubbers in the past, recent evidence, based on a series of field interviews conducted by the author, suggests that managers of coal power plants now have incentives to operate their scrubbers properly. China's new policy incentives since 2007 appear well designed to overcome the hurdle of high operation and maintenance costs of SO(2) scrubbers. Furthermore, it is now far more likely that offenders will be caught and punished. Continuous emission monitoring systems have played a key role in this change of attitudes. Plant inspections have become much more common, facilitated by a significant increase in the number of inspectors and the fact that the 461,000-megawatt SO(2) scrubbers at the end of 2009 were located in only 503 coal power plants, making frequent inspections little constrained by the shortage of inspectors. Because SO(2) is the precursor of sulfate particles believed to cause significant cooling effects on climate, China's SO(2) mitigation may make it more urgent to control the world's greenhouse gas emissions. PMID:21126067

Xu, Yuan

2011-01-15

360

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

361

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

362

Modelling the spatial distribution of SO2 and NOx emissions in Ireland.  

PubMed

The spatial distributions of sulphur dioxide (SO2) and nitrogen oxides (NOx) emissions are essential inputs to models of atmospheric transport and deposition. Information of this type is required for international negotiations on emission reduction through the critical load approach. High-resolution emission maps for the Republic of Ireland have been created using emission totals and a geographical information system, supported by surrogate statistics and landcover information. Data have been subsequently allocated to the EMEP 50 x 50-km grid, used in long-range transport models for the investigation of transboundary air pollution. Approximately two-thirds of SO2 emissions in Ireland emanate from two grid-squares. Over 50% of total SO2 emissions originate from one grid-square in the west of Ireland, where the largest point sources of SO2 are located. Approximately 15% of the total SO2 emissions originate from the grid-square containing Dublin. SO2 emission densities for the remaining areas are very low, < 1 t km-2 year-1 for most grid-squares. NOx emissions show a very similar distribution pattern. However, NOx emissions are more evenly spread over the country, as about 40% of total NOx emissions originate from road transport. PMID:11234533

de Kluizenaar, Y; Aherne, J; Farrell, E P

2001-01-01

363

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

364

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

365

Volcanic Ash and SO2 plume retrievals at Mt. Etna using polar and geostationary satellite measurements  

NASA Astrophysics Data System (ADS)

Mt. Etna (37.45°N, 15.01°E), located in the eastern part of Sicily (Italy), is one the major degassing volcanoes in the world. Its general quiescent state is periodically interrupted by eruptive crises, during which significant ash and SO2 emissions can reach the area surrounding the volcano, causing problems to the population and in particular to air traffic (Catania and Reggio Calabria airports are nearby). Because SO2 and ash are often emitted by an erupting volcano simultaneously, and as the winds can transport these substances together, a measurement of SO2 can be used, in some circumstances, as a proxy for ash. This is particularly important for aviation, when the volcanic debris has been transported over long distances and the satellite-based ash detection signal is weak. In this work the Thermal InfraRed (TIR) measurements of different polar and geostationary satellites instruments as NOAA-AVHRR, NASA-MODIS and MSG-SEVIRI will be used to retrieve simultaneously ash and SO2 from Mt. Etna volcanic plume. The polar measurements ensure bigger ground pixels resolution while geostationary measurements ensure bigger repetition time then the possibility to follow the volcanic eruption evolution. The volcanic ash detection and retrievals (aerosol optical thickness at 0.55 mm, effective radius and ash mass) are carried out by means of the Brightness Temperature Difference (BTD) technique using the TIR channels centred around 11 and 12 micron. The SO2 is carried out by using a best weighted least squares fit method using the channels centered around 8.7 micron. The simulated TOA radiance Look-Up Table (LUT) needed for both the SO2 column abundance and the ash retrievals have been computed using the MODTRAN 4 Radiative Transfer Model. The ash impact on SO2 retrieval has been also investigated. As test case the Mt. Etna eruptive events in 2006 and 2007 have been analyzed.

Corradini, S.; Merucci, L.; Spinetti, C.; Silvestri, M.; Musacchio, M.; Piscini, A.; Buongiorno, M.

2009-12-01

366

Corrections for OMI SO2 BRD retrievals influenced by row anomalies  

NASA Astrophysics Data System (ADS)

Since June 2007, the Ozone Monitoring Instrument (OMI) Earth radiance data at specific viewing angles have been affected by the row anomaly, which causes large biases in sulfur dioxide (SO2) columns retrieved using the band residual difference (BRD) algorithm. To improve global measurements of atmospheric SO2 from OMI, we developed two correction approaches for the row anomaly effects in the northern latitudes and along the full orbit. Firstly the residual correction approach with median residual from a sliding 10° latitude range, and with that near the Equator was used to remove the anomalous high SO2 columns in the northern latitudes. Secondly, in the case of the row anomaly along the full orbit, the SO2 biases caused by the anomalous ozone (O3) column and underestimated Lambertian effective reflectivity (LER) were reduced, respectively, by using unaffected adjacent O3 column and residual correction with median residual from a sliding 10° latitude range. Comparisons with the OMI SO2 columns processed with median residual from a sliding 30° latitude range have illustrated the drastic improvements of our correction approaches under row anomaly conditions. The consistencies among the SO2 columns inside and outside the row anomaly areas have also demonstrated the effectiveness of our correction approaches under row anomaly conditions. The analyses of the underestimation and the errors caused by the O3 column and LER were conducted to understand the limitations of our correction approaches. The proposed approaches for the row anomaly effects can extend the valid range of OMI SO2 Planetary Boundary Layer (PBL) data produced using the BRD algorithm.

Yan, H.; Chen, L.; Tao, J.; Su, L.; Huang, J.; Han, D.; Yu, C.

2012-11-01

367

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

368

40 CFR 97.721 - Recordation of TR SO2 Group 2 allowance allocations and auction results.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 2 allowance allocations and auction results...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 2 Trading Program § 97.721 Recordation of TR SO2 Group 2 allowance allocations and auction...

2013-07-01

369

40 CFR 97.621 - Recordation of TR SO2 Group 1 allowance allocations and auction results.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Recordation of TR SO2 Group 1 allowance allocations and auction results...CAIR NOX AND SO2 TRADING PROGRAMS TR SO2 Group 1 Trading Program § 97.621 Recordation of TR SO2 Group 1 allowance allocations and auction...

2013-07-01

370

Satellite Observations of NO2 Trend over Romania  

PubMed Central

Satellite-based measurements of atmospheric trace gases loading give a realistic image of atmospheric pollution at global, regional, and urban level. The aim of this paper is to investigate the trend of atmospheric NO2 content over Romania for the period 1996–2010 for several regions which are generally characterized by different pollutant loadings, resulting from GOME-1, SCIAMACHY, OMI, and GOME-2 instruments. Satellite results are then compared with ground-based in situ measurements made in industrial and relatively clean areas of one major city in Romania. This twofold approach will help in estimating whether the trend of NO2 obtained by means of data satellite retrievals can be connected with the evolution of national industry and transportation.

Voiculescu, Mirela; Georgescu, Lucian

2013-01-01

371

Satellite observations of NO2 trend over Romania.  

PubMed

Satellite-based measurements of atmospheric trace gases loading give a realistic image of atmospheric pollution at global, regional, and urban level. The aim of this paper is to investigate the trend of atmospheric NO2 content over Romania for the period 1996-2010 for several regions which are generally characterized by different pollutant loadings, resulting from GOME-1, SCIAMACHY, OMI, and GOME-2 instruments. Satellite results are then compared with ground-based in situ measurements made in industrial and relatively clean areas of one major city in Romania. This twofold approach will help in estimating whether the trend of NO2 obtained by means of data satellite retrievals can be connected with the evolution of national industry and transportation. PMID:24453819

Constantin, Daniel-Eduard; Voiculescu, Mirela; Georgescu, Lucian

2013-01-01

372

Sulfur Isotope Fractionation Due to SO2 Photolysis in the Atmosphere  

NASA Astrophysics Data System (ADS)

The discovery of unusual (i.e. mass-independent) sulfur isotope fractionation (or MIF) in Archean and Paleoproterozoic sedimentary rocks has promised to yield insights into the rise of O2 and the nature of the sulfur cycle on ancient Earth [1], but interpretation has been hampered by the lack of a clear mechanism for the sulfur isotope signature. Proposed MIF mechanisms include SO2 photolysis [1-4], atmospheric S3 (thiozone) formation, and thermal sulfate reduction in sediments [5]. Studies focusing only on SO2 photolysis, including measurements of isotopic cross sections [6], have yielded results differing greatly from theory [4], and have resulted in improbable interpretations [7]. In addition to ancient rocks, there are sulfur isotope MIF signatures in polar ice core sulfates associated with massive Plinian eruptions over the past ~1000 years (e.g., [8]). The ice core MIF signatures differ significantly from the ancient Earth MIF signatures, suggesting a different source mechanism. SO2 photolysis can generate sulfur isotope MIF signatures in two ways: 1) self-shielding by an optically-thick column of SO2, and 2) isotope-dependent differences in absorption line intensities and widths, which are espcially important for optically-thin conditions. The MIF signatures in ice core sulfates appear to be consistent with self-shielding in an optically-thick plume, but the Archean MIF clearly is not. To address the optically-thin case, we've made high-resolution ultraviolet cross section measurements of the sulfur isotopologues of SO2 made with the UV FTS at Imperial College. We measured cross sections at 1 cm-1 spectral resolution for 32SO2, 33SO2, 34SO2 and for a 36SO2/34SO2 mixture. Incorporating these cross sections into a simple atmospheric photochemical model with a solar UV flux, we find sulfur MIF signatures for SO and S that.are consistent with the Archean pyrites. We also find that additional mass-dependent fractionation during self-shielding by 32SO2 places an upper limit on the SO2 mixing ratio of ~1 ppb. Our results imply that SO2 photolysis alone is responsible for most of the Archean sulfur MIF record, and that sulfur MIF is a good proxy for the rise of O2 in the earliest Paleoproterozoic. [1] Farquhar (2000) Science 289, 756-758. [2] Farquhar (2001) JGR 106, 32829-32840. [3] Pavlov & Kasting (2002) Astrobiology 2, 27-41. [4] Lyons (2007) GRL 34, L22811. [5] Watanabe et al. Science 324, 370-372. [6] Danielache et al. (2008) JGR 113, D17314. [7] Ueno et al. (2009) PNAS 106, 14784-17789. [8] Baroni et al. (2007) Science 315, 84-87.

Lyons, J. R.; Blackie, D.; Stark, G.; Pickering, J.

2012-12-01

373

Comparison of High Temporal Resolution SO2 Emission Rates and Geophysical Data at Central American Volcanoes  

NASA Astrophysics Data System (ADS)

Recently developed ultraviolet cameras present a significant improvement in the field of volcanic SO2 measurements. Older instruments utilized for measurement of SO2 emissions in volcanic plumes (e.g., COSPEC, mini-DOAS, FLYSPEC) are often limited in their accuracy by plume and volcano geometry, uncertainties in plume velocity, plume variability over the course of a single measurement, and low temporal resolution (generally at least 1 minute per measurement, more often <10 measurements per day). In contrast, UV cameras, with their data's synoptic nature, allow for investigation of the high degree of variability in plumes and offer the opportunity to measure SO2 flow rates (as a proxy for volcanic emission rates) at any number of locations within the image, including at or very near the vent. Plume velocities can be derived from UV camera data time series, eliminating the often erroneous estimations of plume velocity based on wind speed. Temporal resolution of the SO2 dataset is also much improved with the camera able to yield SO2 emission rates at sampling frequencies approaching 1 Hz. The superior temporal resolution facilitates comparison to other volcanic datasets, such as seismicity, microgravity, and deformation. UV camera time series from Fuego volcano, Guatemala, and Masaya volcano, Nicaragua indicate that SO2 flow rates at these volcanoes may double over the course of <10 minutes, and subsequently return to low levels on the same time scale. Though some of the variations in SO2 flow rate are apparently due to wind eddies or other small scale atmospheric variations near the vent, other variations are likely to be real variations in emission rate that are directly related to volcanic processes. These fluctuations are evaluated in relation to simultaneous acoustic and seismic datasets in an attempt to understand the nature of such fluctuations. We present the latest improvements to current algorithms for the processing of UV camera data, including advances in automatic derivations of plume velocity, as well as preliminary integration of camera-derived SO2 emission rates with other geophysical datasets from Fuego, Masaya, and other Central American volcanoes. The high temporal resolution of the UV camera's dataset offers a new opportunity for evaluation, alongside concurrent seismic and acoustic datasets, of variations in SO2 emission rate on a short time scale.

Nadeau, P. A.; Waite, G. P.; Palma, J. L.; Dalton, M. P.; Watson, I. M.

2008-12-01

374

Atmospheric particle formation from the ozonolysis of alkenes in the presence of SO 2  

NASA Astrophysics Data System (ADS)

Laboratory studies on the formation of new particles have been performed in a flow tube in the system O 3/alkene/SO 2 using ?-pinene, trans-butene, and tetramethylethylene (TME) as model alkenes. Reactant concentrations were kept close to atmospheric conditions. In the absence of SO 2, no particle formation was observed. The number of newly formed particles measured in the presence of SO 2 was found to be H 2SO 4-controlled, whereas a distinct contribution of different organic products from the ozonolysis was not discovered. Scavenger experiments for OH radicals revealed that the main fraction of H 2SO 4 produced arose from OH+SO 2. An additional pathway for H 2SO 4, probably Criegee Intermediate+SO 2, accounted for 26% ( ?-pinene), 23% ( trans-butene), and 42% (TME) of the total amount of H 2SO 4 formed. For conditions where particle formation occurred in the flow tube, H 2SO 4 concentrations of a few 10 7 molecule cm -3 were calculated, similar to observations in the atmosphere. Under the experimental conditions used, an analysis of the particle volume indicated that the organic ozonolysis products did not influence the particle growth significantly.

Berndt, Torsten; Böge, Olaf; Stratmann, Frank

375

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

376

Reactive adsorption of SO2 on activated carbons with deposited iron nanoparticles.  

PubMed

The effect of iron particle size anchored on the surface of commercial activated carbon on the removal of SO(2) from a gas phase was studied. Nanosize iron particles were deposited using forced hydrolysis of FeCl(3) with or without H(3)PO(4) as a capping agent. Dynamic adsorption experiments were carried out on either dry or pre-humidified materials and the adsorption capacities were calculated. The surface of the initial and exhausted materials was extensively characterized by microscopic, porosity, thermogravimetric and surface chemistry. The results indicate that the SO(2) adsorption capacity increased two and half times after the prehumidification process owing to the formation of H(2)SO(4) in the porous system. Iron species enhance the SO(2) adsorption capacity only when very small nanoparticles are deposited on the pore walls as a thin layer. Large iron nanoparticles block the ultramicropores decreasing the accessibility of the active sites and consuming oxygen that rest adsorption centers for SO(2) molecules. Iron nanoparticles of about 3-4 nm provide highly dispersed adsorption sites for SO(2) molecules and thus increase the adsorption capacity of about 80%. Fe(2)(SO(4))(3) was detected on the surface of exhausted samples. PMID:23333487

Arcibar-Orozco, Javier A; Rangel-Mendez, J Rene; Bandosz, Teresa J

2013-02-15

377

Field investigations of nitrogen dioxide (NO2) exchange between plants and the atmosphere  

NASA Astrophysics Data System (ADS)

The nitrogen dioxide (NO2) exchange between the atmosphere and needles of Picea abies L. (Norway Spruce) was studied under uncontrolled field conditions using a dynamic chamber system. This system allows measurements of the flux density of the reactive NO-NO2-O3 triad and additionally of the non-reactive trace gases CO2 and H2O. For the NO2 detection a highly NO2 specific blue light converter was used, which was coupled to chemiluminescence detection of the photolysis product NO. This NO2 converter excludes known interferences with other nitrogen compounds, which occur by using more unspecific NO2 converters. Photo-chemical reactions of NO, NO2, and O3 inside the dynamic chamber were considered for the determination of NO2 flux densities, NO2 deposition velocities, as well as NO2 compensation point concentrations. The calculations based on a bi-variate weighted linear regression analysis (y- and x-errors considered). The NO2 deposition velocities for spruce, based on projected needle area, ranged between 0.07 and 0.42 mm s-1. The calculated NO2 compensation point concentrations ranged from 7.4 ± 6.40 to 29.0 ± 16.30 nmol m-3 (0.17-0.65 ppb) but the compensation point concentrations were all not significant in terms of compensation point concentration is unequal zero. These data challenge the existence of a NO2 compensation point concentration for spruce. Our study resulted in lower values of NO2 gas exchange flux densities, NO2 deposition velocities and NO2 compensation point concentrations in comparison to most previous studies. It is essential to use a more specific NO2 analyzer and to consider photo-chemical reactions between NO, NO2, and O3 inside the chamber.

Breuninger, C.; Meixner, F. X.; Kesselmeier, J.

2012-07-01

378

Field investigations of nitrogen dioxide (NO2) exchange between plants and the atmosphere  

NASA Astrophysics Data System (ADS)

The nitrogen dioxide (NO2) exchange between the atmosphere and needles of Picea abies L. (Norway Spruce) was studied under uncontrolled field conditions using a dynamic chamber system. This system allows measurements of the flux density of the reactive NO-NO2-O3 triad and additionally of the non-reactive trace gases CO2 and H2O. For the NO2 detection a highly NO2 specific blue light converter was used, which was coupled to chemiluminescence detection of the photolysis product NO. This NO2 converter excludes known interferences with other nitrogen compounds, which occur by using more unspecific NO2 converters. Photo-chemical reactions of NO, NO2, and O3 inside the dynamic chamber were considered for the determination of NO2 flux densities, NO2 deposition velocities, as well as NO2 compensation point concentrations. The calculations are based on a bi-variate weighted linear regression analysis (y- and x-errors considered). The NO2 deposition velocities for spruce, based on projected needle area, ranged between 0.07 and 0.42 mm s-1. The calculated NO2 compensation point concentrations ranged from 2.4 ± 9.63 to 29.0 ± 16.30 nmol m-3 (0.05-0.65 ppb) but the compensation point concentrations were all not significant in terms of compensation point concentration is unequal to zero. These data challenge the existence of a NO2 compensation point concentration for spruce. Our study resulted in lower values of NO2 gas exchange flux densities, NO2 deposition velocities and NO2 compensation point concentrations in comparison to most previous studies. It is essential to use a more specific NO2 analyzer than used in previous studies and to consider photo-chemical reactions between NO, NO2, and O3 inside the chamber.

Breuninger, C.; Meixner, F. X.; Kesselmeier, J.

2013-01-01

379

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

380

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

381

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

382

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

383

Ultrafine porous carbon fibers for SO2 adsorption via electrospinning of polyacrylonitrile solution.  

PubMed

This work describes the potential capability of ultrafine porous carbon fibers (UPCF) prepared via electrospinning in the removal of SO2 from a mixture gas stream. A series of conventional PCF (CPCF) and ultrafine PCF (UPCF) were produced under the identical conditions and UPCF was also modified. Compared to the CPCF, experimental results showed that the UPCF had a better adsorption capacity for SO2 due to its higher surface area and microporous volume. After the modification of the UPCF, adsorption capacities of UPCF for SO2 were improved further via increasing the N-containing amount of UPCF and substrate which was followed by few changes in its specific surface area. The optimum concentration of modified reagent is 10%. From the results of the fatigue test, it has been found that both the UPCF and the modified UPCF showed a good durability. PMID:18783785