Note: This page contains sample records for the topic gases so2 no2 from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

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

2

Differential Optical Absorption Spectroscopy (DOAS) using Targets: SO2 and NO2 Measurements in Montevideo City  

Microsoft Academic Search

SO2 and NO2 were remotely measured in a main street of Montevideo city using Multiaxis-Differential Optical Absorption Spectroscopy (MAX-DOAS) combined with on-field selected targets. Target-based measurements are the basis of a new experimental procedure called Topographic Target Light scattering-DOAS (TOTAL-DOAS) that provides a well define absorption path to measure the near surface distribution of trace gases in the boundary layer.

Ilia Louban; Gustavo Píriz; Ulrich Platt; Erna Frins

2008-01-01

3

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

4

Development of a nondispersive UV-visible analyzer for simultaneous measurements of SO2 and NO2 in stacks emissions  

Microsoft Academic Search

12 Non-dispersive analyzers have been used for measurement of gases for many years and were recently introduced as on-line meters for continuous stack emission measurements in industrial plants. SO2 and NO2 are among the most important gases in the emissions of the petrochemical industry. The development of a UV-visible meter for these gases is presented. It consists of three optical

Daniel C. Schinca; Gustavo Ratto; Fabian Videla; Edmundo Rodriguez; Roberto E. Di Paolo; Jorge O. Tocho

2001-01-01

5

Simultaneous determination of SO(2), NO and NO(2) in air by differential pulse polarography.  

PubMed

The method of Garber and Wilson for SO(2) determination has been tested on real samples of air. The results demonstrate the possibility of simultaneous determination of SO(2), NO and NO(2) in the sample. Detection limits as low as 7 mul/m(3) for SO(2) and about 50 mul/m(3) for nitric oxides can be reached. PMID:18962564

Bruno, P; Caselli, M; Monica, M D; Di Fano, A

1979-11-01

6

GROWTH RESPONSE IN SPINACH TO SEQUENTIAL AND SIMULTANEOUS EXPOSURE TO NO2 AND SO2  

EPA Science Inventory

Spinach (Spinacia oleracea) was exposed intermittently to NO2 and SO2 (2 hours/week; 0.8 or 1.5ppm) in a simultaneous or sequential fashion over the 42-day growth period. Nighttime simultaneous exposure to NO2 and SO2 reduced growth and altered assimilate partitioning to the root...

7

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

8

Evaluation of SO 2 and NO 2 concentration levels in Vilnius (Lithuania) using passive diffusion samplers  

Microsoft Academic Search

The method of passive diffusion samplers has been used for evaluation of SO2 and NO2 concentration levels in the Lithuanian capital Vilnius. It was analysed about 70 diffusion tubes twice per 4 seasons during 1995–1996 for each component, thus about 600 samplers were exposed and analysed including control parallel sampling. The measurement results show that the SO2 concentrations levels depend

D. Perkauskas; A. Mikelinskiene

1998-01-01

9

UV Fourier transform measurements of tropospheric O3, NO2, SO2, benzene, and toluene.  

PubMed

Using the differential optical absorption spectroscopy (DOAS) technique and a Fourier transform spectrometer, NO2, SO2, O3, benzene. and toluene were measured during three measurement campaigns held in Brussels in 1995, 1996, and 1997. The O3 concentrations could be explained as the results of the local photochemistry and the dynamical properties of the mixing layer. NO2 concentrations were anti-correlated to the O3 concentrations, as expected. SO2 also showed a pronounced dependence on car traffic. Average benzene and toluene concentrations were, respectively 1.7 ppb and between 4.4 and 6.6 pbb, but high values of toluene up to 98.8 ppb were observed. SO2 concentrations and to a lesser extent, those of NO2 and 03, were dependent on the wind direction. Ozone in Brussels has been found to be influenced by the meteorological conditions prevailing in central Europe. Comparisons with other measurements have shown that 03 and SO2 data are in general in good agreement, but our NO2 concentrations seem to be generally higher. PMID:11806447

Vandaele, A C; Tsouli, A; Carleer, M; Colin, R

2002-01-01

10

REMOVAL OF SO2 FROM INDUSTRIAL WASTE GASES  

EPA Science Inventory

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

11

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Test procedures for methods for SO2, CO, O3, and NO2. 53...AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods § 53.32...

2013-07-01

12

Synergistic effect between NO2 and SO2 in their adsorption and reaction on gamma-alumina.  

PubMed

Field measurements showed that there exists a correlation between nitrate and sulfate on mineral dust. In this work, the synergistic mechanism of adsorption and reaction between SO2 and NO2 on gamma-alumina was studied using in situ diffusion reflectance infrared Fourier spectroscopy (in situ DRIFTS) and temperature programmed desorption (TPD). The results revealed that the reaction pathway of NO2 adsorbed on alumina was altered in the presence of SO2. In the absence of SO2, nitrite was found to be an intermediate in the oxidation of NO2 to surface nitrate species. However, in the presence of SO2, the formation of nitrite was inhibited and a new intermediate, dinitrogen tetraoxide (N2O4), was observed. On the other hand, surface tetravalent sulfur species S(IV), including bisulfite and sulfite, were oxidized to sulfate in air condition when NO2 was present. The atmospheric implication of this synergistic effect was also discussed. PMID:18578482

Ma, Qingxin; Liu, Yongchun; He, Hong

2008-06-26

13

Present state of eb removal of so2 and nox from combustion flue gases in Brazil  

NASA Astrophysics Data System (ADS)

Environmental problems caused by the increased world energy demands are becoming of growing importance and Brazil is now starting to set limits to the emission of toxic gases. The development of technologies for removal of these gases are therefore necessary and this work shows the present state of the technology of SO2 and NOX removal by electron beam irradiation in Brazil. Data concerning the increasing energy demand in Brazil and the environmental governmental measures are presented, along with the design and implementation of a laboratory pilot plant for the electron beam flue gases removal process located at IPEN-CNEN/SP.

Poli, D. C. R.; Osso, J. A.; Rivelli, V.; Vieira, J. M.; Lugão, A. B.

1995-09-01

14

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

15

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

EPA Science Inventory

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

16

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

EPA Science Inventory

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

17

NO2 and SO2 dispersion modeling and relative roles of emission sources over Map Ta Phut industrial area, Thailand.  

PubMed

Map Ta Phut industrial area (MA) is the largest industrial complex in Thailand. There has been concern about many air pollutants over this area. Air quality management for the area is known to be difficult, due to lack of understanding of how emissions from different sources or sectors (e.g., industrial, power plant, transportation, and residential) contribute to air quality degradation in the area. In this study, a dispersion study of NO2 and SO2 was conducted using the AERMOD model. The area-specific emission inventories of NOx and SO2 were prepared, including both stack and nonstack sources, and divided into 11 emission groups. Annual simulations were performed for the year 2006. Modeled concentrations were evaluated with observations. Underestimation of both pollutants was Jbund, and stack emission estimates were scaled to improve the modeled results before quantifying relative roles of individual emission groups to ambient concentration overfour selected impacted areas (two are residential and the others are highly industrialized). Two concentration measures (i.e., annual average area-wide concentration or AC, and area-wide robust highest concentration or AR) were used to aggregately represent mean and high-end concentrations Jbfor each individual area, respectively. For AC-NO2, on-road mobile emissions were found to be the largest contributor in the two residential areas (36-38% of total AC-NO2), while petrochemical-industry emissions play the most important role in the two industrialized areas (34-51%). For AR-NO2, biomass burning has the most influence in all impacted areas (>90%) exceptJor one residential area where on-road mobile is the largest (75%). For AC-SO2, the petrochemical industry contributes most in all impacted areas (38-56%). For AR-SO2, the results vary. Since the petrochemical industry was often identified as the major contributor despite not being the largest emitter, air quality workers should pay special attention to this emission group when managing air quality for the MA. PMID:22916441

Chusai, Chatinai; Manomaiphiboon, Kasemsan; Saiyasitpanich, Phirun; Thepanondh, Sarawut

2012-08-01

18

Monitoring the SO2 concentration at the summit of Mt. Fuji and a comparison with other trace gases during winter  

Microsoft Academic Search

An SO2 continuous monitor consisting of a commercially available pulsed UV fluorescence instrument with zero and span gas calibration was installed at the summit of Mt. Fuji (3776 m asl) in September 2002. The system produces data with a time resolution comparable with other trace gases. The instrumental feasibility was tested onsite, and the SO2 concentration level at the summit

Yasuhito Igarashi; Yosuke Sawa; Katsuhiro Yoshioka; Hidekazu Matsueda; Kenji Fujii; Yukiko Dokiya

2004-01-01

19

Interconversion of chromium species during air sampling: effects of O3, NO2, SO2, particle matrices, temperature, and humidity.  

PubMed

The interconversion 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) interconversion in the basic filter medium under typical sampling conditions. In the chamber tests, isotopically enriched (53)Cr(VI) and (50)Cr(III) were spiked on diesel particulate matter (DPM) and secondary organic aerosol (SOA) that were precollected 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 h 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 (53)Cr(VI) reduction, with (53)Cr(VI) recovery of 31.7 ± 15.8% (DPM) and 42.0 ± 7.9% (SOA). DPM and SOA matrix induced (53)Cr(VI) reduction when exposed to clean air while reactive oxygen species in SOA could promote (50)Cr(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) interconversion during sampling. Correction of the interconversion using USEPA method 6800 is recommended to improve accuracy of ambient Cr(VI) measurements. PMID:23550818

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

2013-04-18

20

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

Code of Federal Regulations, 2013 CFR

...Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2 C Figure...AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods Pt. 53,...

2013-07-01

21

Monitoring the SO2 concentration at the summit of Mt. Fuji and a comparison with other trace gases during winter  

NASA Astrophysics Data System (ADS)

An SO2 continuous monitor consisting of a commercially available pulsed UV fluorescence instrument with zero and span gas calibration was installed at the summit of Mt. Fuji (3776 m asl) in September 2002. The system produces data with a time resolution comparable with other trace gases. The instrumental feasibility was tested onsite, and the SO2 concentration level at the summit was thereafter routinely observed. The present detection capability of the system, expressed in terms of the critical level (Lc, definition by International Union of Pure and Applied Chemistry and International Organization for Standardization), was estimated to be about 0.05 ppbv. Thus it was difficult to observe the temporal change of very low background SO2. However, the system is satisfactory for observing episodic transport of SO2, particularly during winter. No high SO2 episodes were observed during summer, in contrast to winter. One extraordinary episode was observed in late October 2003, the only one attributable to the Miyake-jima SO2 volcanic plume. High SO2 episodes were more evident (with longer duration and higher concentration level) in February 2003 among the winter months observed. Typical February conditions were determined using backward trajectory, a surface weather map, and other indicators. A comparison of the temporal changes in SO2, CO, and 222Rn concentrations in the winter months suggests that these gases in the free troposphere over Japan may have been transported together in most cases from the same source regions somewhere in the Asian continent. The correlation between SO2 and 222Rn in such episodes may also suggest a short timescale for transport from the source to Mt. Fuji of within a few days. The chemical time series data of SO2 at Mt. Fuji is important for understanding the free tropospheric chemical nature, such as the Asian outflow over the North Pacific.

Igarashi, Yasuhito; Sawa, Yosuke; Yoshioka, Katsuhiro; Matsueda, Hidekazu; Fujii, Kenji; Dokiya, Yukiko

2004-09-01

22

Treatment of toxic gases SO2 and NO(x) by electron beam irradiation  

Microsoft Academic Search

The removal of SO2 and NO(x) by electron beam irradiation will be studied using a small scale flow system which is being set up in order to obtain basic data for the process technical and economical feasibility concerning industrial applications. The gas irradiation will be performed using a Electron Beam Accelerator with 1.5 MeV power, 25 mA current from Radiation

Dora Decastro Rubio Poli; Jose Mauro Vieira; Clelia Aparecida Decampos

1993-01-01

23

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

Microsoft Academic Search

In August–September 2006, as part of the Second Texas Air Quality Study, NO2 and SO2 emissions from the Houston Ship Channel and Texas City industrial areas were quantified using mobile mini-differential optical absorption spectroscopy instruments. The measured NO2 emissions from the Houston Ship Channel and Texas City industrial areas were 2542 and 452 kg h?1, respectively, yielding NOx emissions 70%

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

2010-01-01

24

The effect of SO 2, NO 2, NO and O 3 on the corrosion of unalloyed carbon steel and weathering steel—The results of laboratory exposures  

Microsoft Academic Search

Laboratory exposures of unalloyed steel and weathering steel have been carried out in humid air containing single air pollutants (SO2, NO2, NO, O3 and laboratory air) in order to investigate their role in atmospheric corrosion. Realistic pollutant supply rates normally encountered in outdoor exposures were chosen for the experiments. Some experiments resulted in the formation of rust protrusions and corrosion

S. Oesch

1996-01-01

25

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

26

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

27

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

Microsoft Academic Search

We applied the Multi-GAS technique to measure compositions of the volcanic plumes continuously discharged from summit craters of Voragine, Northeast and Bocca Nuova at Mount Etna, in an attempt to estimate compositions of the source volcanic gases. The estimated CO2\\/SO2 and H2O\\/CO2 ratios of the volcanic gases show a large variation ranging from 0.6 to 30 and from 1 to

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

2008-01-01

28

Mechanism of pulse corona induced plasma chemical process for removal of NOx and SO2 from combustion gases  

Microsoft Academic Search

SO2 and NOx removal by streamer corona discharges is proposed, and the role played by H2O and NH3 in the system is discussed. The results show that: (1) the ion-molecule reactions play an important role in the SO2 and NOx processes as well as the radicals reactions; (2) the effects of gas temperature and electron energy cannot be neglected in

J. S. Chang; S. Masuda

1988-01-01

29

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

Microsoft Academic Search

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

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

2007-01-01

30

MAX-DOAS Measurements of ClO, SO 2 and NO 2 in the MidLatitude Coastal Boundary Layer and a Power Plant Plume  

Microsoft Academic Search

Remote sensing techniques have been preferred for measurements of atmospheric trace gases because they allow direct measurement\\u000a without pre- and\\/or post-treatment in the laboratory. UV–visible absorption measurement techniques have been used for ground-based\\u000a remote sensing of atmospheric trace species. The multi-axis differential optical absorption spectroscopy (MAX-DOAS) technique,\\u000a one of the remote sensing techniques for air quality measurement, uses scattered sunlight

Chulkyu Lee; Young J. Kim; Hanlim Lee; Byeong C. Choi

31

Comparative modelling of NOx and SO2 removal from pollutant gases using pulsed-corona and silent discharges  

NASA Astrophysics Data System (ADS)

A comparative modelling of pulsed-corona and silent discharges for removal of NOx, NyOx, SO2, CO and CH2O using operating equipment is presented. The main purpose is to compare, by modelling, the energy efficiency on removal of toxic impurities between two types of discharges at similar gas composition and temperature. Three different gas compositions: diesel engine exhaust, methane combustion products and pollutant air are considered. The simulation is based on an approximate mathematical model for plasma cleaning of a waste gas. The influence of non-uniform species distributions arising from a great number of streamer or microdischarge channels in a discharge chamber is taken into account. The modelling is carried out for a pulse series, considering after each discharge pulse the chemical and diffusion processes inside and outside the streamer trace. The distinctions of the cleaning processes in the pulsed-corona and barrier discharges are presented. It is also recommended when each of the examined discharges should be used.

Filimonova, E. A.; Amirov, R. H.; Kim, H. T.; Park, I. H.

2000-07-01

32

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

33

Application of a long-path differential optical absorption spectrometer (LP-DOAS) on the measurements of NO 2, SO 2, O 3, and HNO 2 in Gwangju, Korea  

Microsoft Academic Search

A differential optical absorption spectrometer (DOAS) technique has been applied to monitor airborne trace pollutants including NO2, SO2, O3, and HNO2 in the ultraviolet (UV) region (290–350nm) over a 1.5km beam path (two ways) during an intensive measurement campaign held at Gwangju, Korea (March 2002). Their mean mixing ratios (and standard deviations) were computed as 11.3 (8.8), 1.9 (1.7), 17.1

Jeongsoon Lee; Ki-Hyun Kim; Young J. Kim; Jaihoon Lee

2008-01-01

34

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

35

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

PubMed

A laser flash photolysis-resonance fluorescence technique has been employed to measure rate coefficients and physical vs. reactive quenching branching ratios for O((1)D) deactivation by three potent greenhouse gases, SO(2)F(2)(k(1)), NF(3)(k(2)), and SF(5)CF(3)(k(3)). In excellent agreement with one published study, we find that k(1)(T) = 9.0 x 10(-11) exp(+98/T) cm(3) molecule(-1) s(-1) and that the reactive quenching rate coefficient is k(1b) = (5.8 +/- 2.3) x 10(-11) cm(3) molecule(-1) s(-1) independent of temperature. We find that k(2)(T) = 2.0 x 10(-11) exp(+52/T) cm(3) molecule(-1) s(-1) with reaction proceeding almost entirely (approximately 99%) by reactive quenching. Reactive quenching of O((1)D) by NF(3) 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 NF(3). Deactivation of O((1)D) by SF(5)CF(3) is slow enough (k(3) < 2.0 x 10(-13) cm(3) molecule(-1) s(-1) at 298 K) that reaction with O((1)D) is unimportant as an atmospheric removal mechanism for SF(5)CF(3). The kinetics of O((1)D) reactions with SO(2) (k(4)) and CS(2) (k(5)) have also been investigated at 298 K. We find that k(4) = (2.2 +/- 0.3) x 10(-10) and k(5) = (4.6 +/- 0.6) x 10(-10) cm(3) molecule(-1) s(-1); branching ratios for reactive quenching are 0.76 +/- 0.12 and 0.94 +/- 0.06 for the SO(2) and CS(2) reactions, respectively. All uncertainties reported above are estimates of accuracy (2sigma) and rate coefficients k(i)(T) (i = 1,2) calculated from the above Arrhenius expressions have estimated accuracies of +/- 15% (2sigma). PMID:20133693

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

2010-02-04

36

CFD simulation of dilute phase gas–solid riser reactors: part II—simultaneous adsorption of SO 2–NO x from flue gases  

Microsoft Academic Search

Simultaneous adsorption of SO2–NOx in a riser configuration is a novel route for flue gas cleaning. The riser operates at a low flux (2kgm?2s?1) of small diameter (dp=60?m) Na-?-Al2O3 sorbent particles. The reaction scheme is adopted from previous work (Ind. Eng. Chem. Res. 40 (2001) 119), without adjusting any of the kinetic parameters. The significant concentration gradient between the gas

A. K. Das; J. De Wilde; G. J. Heynderickx; G. B. Marin

2004-01-01

37

Evaluation of gases, condensates, and SO2 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

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

1990-01-01

38

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

39

Application of a long-path differential optical absorption spectrometer (LP-DOAS) on the measurements of NO(2), SO(2), O(3), and HNO(2) in Gwangju, Korea.  

PubMed

A differential optical absorption spectrometer (DOAS) technique has been applied to monitor airborne trace pollutants including NO(2), SO(2), O(3), and HNO(2) in the ultraviolet (UV) region (290-350 nm) over a 1.5 km beam path (two ways) during an intensive measurement campaign held at Gwangju, Korea (March 2002). Their mean mixing ratios (and standard deviations) were computed as 11.3 (8.8), 1.9 (1.7), 17.1 (19.3), and 0.5 (0.4)ppbv, respectively. As a means to evaluate the performance of the long-path DOAS (LP-DOAS) system with conventional point monitoring systems (PMS), correlation analysis was conducted between the two data sets. These data sets were then inspected to account for the influence of the environmental conditions on the correlation strength between the two systems, especially with respect to light level and wind speed. To facilitate the comparison, correlation analyses were conducted after dividing the data sets for those parameters into several classes. The strength of the correlations between DOAS and meteorological parameters was also examined to evaluate their effects on the DOAS performance. It was found that, among the four pollutant species, O(3) is the most sensitive to changes in meteorological conditions in relation with atmospheric mixing conditions. The overall results of our study indicate that open-path monitoring techniques can be used to effectively diagnose air quality and be substituted for the conventional point monitoring methods with the proper consideration of those parameters affecting the DOAS sensitivity (e.g., light level and wind speed). PMID:17335958

Lee, Jeongsoon; Kim, Ki-Hyun; Kim, Young J; Lee, Jaihoon

2007-03-01

40

Study of a high SO2 event observed over an urban site in western India  

NASA Astrophysics Data System (ADS)

Continuous measurements of SO2, NOx and O3 along with sampling based measurements of CO, CH4, NMHCs and CO2 were carried out during May, 2010 at Ahmedabad. The diurnal variations of SO2 in ambient air exhibited elevated values during the night and lower levels during the sunlit hours. The mean concentration of SO2 during the study period was 0.95 ± 0.88 ppbv. However, the ambient SO2 exceeded 17 ppbv in the night of 20 May, 2010. On the same day, tropospheric columnar SO2 from OMI showed almost 350% increase corroborating the surface observations over an extended height regime. This was also the highest columnar value of SO2 during the summer of 2010. Columnar loadings were also found to be high for formaldehyde, precipitable water vapor and aerosol optical depth on 20 May. Elevated concentrations were also recorded for other trace gases like NO2 and O3. Analysis of related data of trace gases indicated characteristics of fresh emissions with dominant contributions from mobile sources during the study period. However, SO2/NO2 ratio of 0.36 during the event period on 20th May connotes non-local influences. Analyses of meteorological parameters suggest combined impacts of transport and inversion causing higher levels of SO2 and other pollutants during 20-21 May. Episodes of such enhancements may perturb chemical and radiative balance of the atmosphere.

Mallik, Chinmay; Venkataramani, S.; Lal, Shyam

2012-05-01

41

NO2Assisted Soot Regeneration Behavior in a Diesel Particulate Filter with Heavy-Duty Diesel Exhaust Gases  

Microsoft Academic Search

A major concern in operating a diesel engine is how to reduce the soot emission from the exhaust gases, as soot has a negative effect on both human health and the environment. More stringent emission regulations make the diesel particulate filter (DPF) an indispensable after-treatment component to reduce diesel soot from exhaust gases. The most important issue in developing an

Jong Hun Kim; Man Young Kim; Hyong Gon Kim

2010-01-01

42

A laboratory study on the uptake of HCl, HNO 3, and SO 2 gas by ice crystals and the effect of these gases on the evaporation rate of the crystals  

Microsoft Academic Search

The results of our new and earlier laboratory studies on the uptake of gases by ice crystals are summarized in terms of (1) the equilibrium phase diagram for a system gas\\/H2O, (2) the effect of these gases on the evaporation rate of ice crystals, and (3) in terms of the uptake of the gases by water drops. It is shown

K Diehl; S. K Mitra; H. R Pruppacher

1998-01-01

43

SO2 Measurements with Sciamachy  

Microsoft Academic Search

Three years of measurements from the SCIAMACHY instrument on ENVISAT were analysed for tropospheric SO2 absorption. Both volcanic and anthropogenic emissions were identified in the data with much better spatial resolution than possible when using GOME data. Radiative transfer modelling studies show a pronounced dependence of the sensitivity on surface albedo and vertical distribution of SO2, but also on wavelength

Andreas Richter; Folkard Wittrock; J. P. Burrows

2006-01-01

44

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

Microsoft Academic Search

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

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

2010-01-01

45

Passive IR SO2 Sensor.  

National Technical Information Service (NTIS)

A remote operating Passive Infrared SO2 Sensor was developed. A system of quantitative measurement for field operation was created with simplicity of operation and minimum of interference as objectives. The complexities of the radiative process limit accu...

J. M. Lepper

1967-01-01

46

New discoveries enabled by OMI SO2 measurements and future missions  

NASA Astrophysics Data System (ADS)

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

Krotkov, Nickolay

2010-05-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

48

Size distributions of fine and ultrafine particles in the city of Strasbourg: correlation between number of particles and concentrations of NO(x) and SO(2) gases and some soluble ions concentration determination.  

PubMed

An Electrical Low Pressure Impactor (ELPI) was used during spring and autumn 2003 in the centre of Strasbourg for the measurement of atmospheric aerosols size distribution. The concentration of NO(x) and SO(2) in air was simultaneously measured with specific analysers. Samples were collected in the range 0.007-10 microm in equivalent aerodynamic diameter size. Number distributions are representative of a pollution originating from urban traffic with a particle size distribution exhibiting a nucleation mode below 29 nm and an accumulation mode around 80 nm in size. A mean particle density equal to 39000+/-35000 total particles per cm(3) with a size ranging from 7 to 10 microm was obtained after a sampling period of 2 weeks in spring. About 86.9% of the number of particles have an aerodynamic diameter below 0.1 microm and 13.1% between 0.1 and 1 microm. Correlation coefficients between the number of particles impacted on each ELPI plate and gas concentrations (SO(2) and NO(x)) showed that the numbers of particles with diameter between 0.10 and 0.62 microm are highly related to the NO(x) concentration. This result indicates that particles are traffic induced since NO(x) is mainly emitted by cars as shown by measurements on various sites. Particles are less clearly correlated to the SO(2) concentration. Particle analysis on different ELPI plates for a sampling period of 2 weeks in autumn showed high level of soluble NO(3)(-), SO(4)(2-) and NH(4)(+) ions. Indeed, up to 90% b.w. of these three species were found in the particle range 0.1-1 microm. The formation of particulate NH(4)NO(3) is favoured by high NO(x) concentration, which induces the formation of gaseous HNO(3). PMID:17275982

Roth, Estelle; Kehrli, Damaris; Bonnot, Karine; Trouvé, Gwénaëlle

2007-02-02

49

Long-range transport of volcanic SO2 over Northern India  

NASA Astrophysics Data System (ADS)

Anthropogenic activities contribute to more than 70% of global sulfur dioxide (SO2) emissions. Among the natural sources of SO2, volcanic emissions can be significant but sporadic contributors. Apart from releasing a plethora of pollutant gases, volcanoes can also impact atmospheric temperatures and radiation balance as was observed after El Chichon (1982) and Mt. Pinatubo (1991) eruptions. The present study deals with episodes of long-range transport of SO2 from Africa to Northern India using multiple 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). In contrast, SO2 monthly averages retrieved from observations across different locations over North India had never exceeded 0.3 DU during the six year period of 2005-2010. The columnar SO2 loadings were a factor of 10 higher than background levels over most of the IGP on the day of impact. These enhanced SO2 levels were, however, not reciprocated in satellite derived NO2 or CO columns, indicating transport from a non-anthropogenic source of SO2. Back-trajectory analysis revealed strong winds in the free troposphere, which originated from a volcanic eruption over Ethiopia. Wind streams and stable atmospheric conditions were conducive to the long-range transport of volcanic plume over the IGP. Increase in aerosol optical depths were observed both from ground-based measurements as well as satellite observations. A well separated layer of aerosols above the boundary layer was 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. Details of this episode of transport in terms of meteorology and dynamics will be presented during the assembly.

Mallik, Chinmay; Joshi, Hema; Chand, D.; Lal, Shyam; Naja, Manish; Venkataramani, S.; Pant, P.

2012-07-01

50

Formation and characterization of the uranyl-SO2 complex, UO2(CH3SO2)(SO2)-.  

PubMed

The uranyl-SO(2) adduct, UO(2)(CH(3)SO(2))(SO(2))(-), was prepared and characterized by mass spectrometric studies as well as by density functional theory. Collision induced dissociation of UO(2)(CH(3)SO(2))(2)(-) in an ion trap resulted in the formation of UO(2)(CH(3)SO(2))(SO(2))(-), which spontaneously reacted with O(2) to give UO(2)(CH(3)SO(2))(O(2))(-), with SO(2) released. The UO(2)(CH(3)SO(2))(SO(2))(-) complex is computed to have a triplet ground state at the B3LYP level, and the SO(2) ligand is coordinated to uranium through two oxygen atoms, similar to the coordination mode of SO(2) in its complexes with hard metals. On the basis of the calculated geometric parameters and vibrational frequencies of the SO(2) ligand, the UO(2)(CH(3)SO(2))(SO(2))(-) complex can be considered as a U(V)O(2)(+) cation coordinated by SO(2)(-) and CH(3)SO(2)(-) anions. The UO(2)(CH(3)SO(2))(O(2))(-) complex is computed to have a peroxo ligand, suggesting that U(V) in UO(2)(CH(3)SO(2))(SO(2))(-) is oxidized to the U(VI) state upon O(2) substitution for SO(2). PMID:23311292

Gong, Yu; Gibson, John K

2013-01-22

51

MODELING OF SO2 OXIDATION IN SMOG  

EPA Science Inventory

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

52

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

53

STATUS OF SO2 SCRUBBING TECHNOLOGIES  

EPA Science Inventory

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

54

Guanidinium-based potentiometric SO2 gas sensor.  

PubMed

An SO2 gas sensor was developed by using a hydrogen sulfite-selective electrode positioned behind a gas-permeable membrane (GPM). The hydrogen sulfite-selective electrode was prepared by incorporating a multicyclic guanidinium ionophore in a plasticized poly(vinyl chloride) membrane. This gas sensor presents important advantages over the conventional Severinghaus-type SO2 gas sensor that contains a pH electrode immersed in an internal solution behind the GPM. The Severinghaus gas sensor suffers interferences from weak acids that can cross the GPM as gases and change the pH of the internal solution. In contrast, in the proposed sensor, the excellent selectivity of the HSO3- electrode and the ability of the GPM to discriminate gaseous from nongaseous species combine to generate the most selective potentiometric SO2 gas sensor reported to date. PMID:9921127

Mowery, M D; Hutchins, R S; Molina, P; Alajarín, M; Vidal, A; Bachas, L G

1999-01-01

55

Emission control of SO2 and NOx by irradiation methods.  

PubMed

Microwave discharges at 2.45 GHz frequency and accelerated electron beams operated at atmospheric pressure in synthetic gas mixtures containing N(2), O(2), CO(2), SO(2), and NO(x) are investigated experimentally for various gas mixture constituents and operating conditions, with respect to their ability to purify exhaust gases. An original experimental unit easily adaptable for both separate and simultaneous irradiation with microwaves and electron beams was set up. The simultaneous treatment with accelerated electron beams and microwaves was found to increase the removal efficiency of NO(x) and SO(2) and also helped to reduce the total required dose rate with approximately 30%. Concomitant removal of NO(x) ( approximately 80%) and SO(2) (>95%) by precipitation with ammonia was achieved. PMID:12573835

Radoiu, Marilena T; Martin, Diana I; Calinescu, Ioan

2003-02-28

56

SO 2 sensing characteristics of Nasicon electrolytes  

Microsoft Academic Search

The SO2 sensing characteristics of the Nasicon electrolyte cells Pt,SO2,O2(I) I Na2SO4 I Nasicon I O2(II) in air, Pt and Pt,SO2,O2(I) l Na2SO4?(BaSO4) I Nasicon I Na2SiO3,Pt have been studied in 5–98 ppm SO2 concentration range at 300–550°C. The cell with the O2 reference electrode was very unstable. However, good agreement between the measured and calculated slopes in the Nernst

Soon-Don Choi; Wan-Young Chung; Duk-Dong Lee

1996-01-01

57

SO(2, 1) and the Hulthen Potential.  

National Technical Information Service (NTIS)

The s-state eigenfunctions of the Schrodinger equation for an electron in a Hulthen potential are shown to form a basis for an irreducible unitary representation of SO(2,1). The properties of this SO(2,1) are then applied to a study of the difference betw...

B. I. Dunlap L. Armstrong

1972-01-01

58

Impacts of acid gases on mercury oxidation across SCR catalyst  

Microsoft Academic Search

A series of bench-scale experiments were completed to evaluate acid gases of HCl, SO2, and SO3 on mercury oxidation across a commercial selective catalytic reduction (SCR) catalyst. The SCR catalyst was placed in a simulated flue gas stream containing O2, CO2, H2O, NO, NO2, and NH3, and N2. HCl, SO2, and SO3 were added to the gas stream either separately

Ye Zhuang; Jason Laumb; Richard Liggett; Mike Holmes; John Pavlish

2007-01-01

59

SO 2 conversion rates at Soufrière Hills volcano, Montserrat, B.W.I  

Microsoft Academic Search

Abstract—Volcanic SO 2 emission,rates are commonly,measured,on plume,cross sections some distance downwind from the active vent; after interacting with other volcanogenic gases, particles and droplets of volcanogenic and\\/or meteoric origin, and atmospheric gases. The emission rates therefore do not necessarily represent the real fluxes, due to the conversion of SO 2 to SO 4 -2 . It is important,to quantify volcanic

Lizzette A. Rodríguez; I. Matthew Watson; Vicky Hards; Graham Ryan; Marie Edmonds; Clive Oppenheimer; Gregg J. S. Bluth

2005-01-01

60

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

61

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

62

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

63

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

64

So2 vertical profile on Venus  

NASA Astrophysics Data System (ADS)

Introduction The distribution of SO2 below the clouds of Venus is an unsettled matter because various entry probes and earth observed values show big differences for the same altitude levels. A new analysis of the SO2 vertical profile with a 'best of' data set [1] is compared to the Vega 1 and Vega 2 results. For the analysis of the SO2 vertical profile two models have been formulated. While one model considers the fast decrease of SO2 with descending altitude and starts with 0 ppmV at the surface, the other model starts with 25 ppmV, as indicated by Vega 1. Although there is a lack of information on the lowest 10 kms of the atmosphere, an analysis should be done to understand the geological evolution and a possible activity on Venus. Vertical Profiles The two models produce two different vertical profiles and with those it was possible to calculate the mass of SO2 in the whole lower atmosphere. It is important to note that SO2 nearly disappears at 69 km height [1,3] while 99,6% of the whole mass is still contained in the lower atmosphere. The difference in the results is based on the different surface values, which have been used. The first model stands in good agreement with the Vega mission data and the second model can be used as an upper limit of SO2 in the atmosphere. The results yield a good estimation of how much SO2 is existent and give new discussion points about volcanic activity on Venus and a possible still unknown SO2 destroying mechanism. References [1] Bertaux, J. et al. (1996) JGR, 101, 12709-12745. [2] de Bergh, C. et al. (2006) Planetary and Space Sci., 54, 1389-1397. [3] Esposito L.W. et al., (1997) Venus II : Geology, Geophysics, Atmosphere, and Solar Wind Environment. Edited by Stephen W. Bougher, D.M. Hunten, and R.J. Philips. Tucson, AZ : University of Arizona Press, 415-458

Duricic, Alen; Leitner, Johannes; Firneis, Maria G.

2010-05-01

65

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

66

SO2 EMISSIONS AND TIME SERIES MODELS  

EPA Science Inventory

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

67

Io's Non-SO2 Spectral Features  

Microsoft Academic Search

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. \\

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

2003-01-01

68

Effect of bioindicators ( Lichen ) expousure with SO2 , NO2 , O3 pollutant in urban environment  

Microsoft Academic Search

Background: lichen , due to the existence of different weather conditions and high sensitivity to air pollutants, especially sulfur dioxide, nitrogen dioxide , ozone as biological indicators of air pollution control is considered. Method: this empirical research, lecanora muralis lichen bag inside of a special contact with the sulfur dioxide concentrations 40, 100 and 200, nitrogen dioxide concentrations 60, 100

Khani M; Vaezi M; Ghanadi E; Shahabpour G

69

Potentiometric Gas Sensors for Oxidic Gases  

Microsoft Academic Search

Solid electrolyte-based electrochemical devices combined with an auxiliary phase of oxyacid salt have, in this decade, emerged as new attractive sensors to detect oxidic gases of CO2, NO, NO2 and SO2. Various combinations of solid electrolytes and auxiliary phases as well as various new single or multi-component auxiliary phases have been exploited to improve the gas sensing properties and stability

Noboru Yamazoe; Norio Miura

1998-01-01

70

Emissions of SO2 and NOx from biofuels in India  

NASA Astrophysics Data System (ADS)

Concentrations of oxides of S and N in the atmosphere are strongly influenced by the emissions taking place from the burning of biofuels. This is particularly important in the developing countries where most of the energy requirement in the rural sector is met from biofuels. An experimental setup has been built to carry out controlled biomass burning and to derive emission factors for SO2 and NOx (NO and NO2) from various biofuels commonly used in India. Using these emission factors and the consumption data obtained from Tata Energy Research Institute's (TERI) Energy Data Directory and Yearbook 1998-99, the budget of SO2 and NOx from biofuels used in India has been estimated as 0.4 ± 0.3 and 1.0 ± 0.4 Tg, respectively, for the year 1990.

Gadi, Ranu; Kulshrestha, U. C.; Sarkar, A. K.; Garg, S. C.; Parashar, D. C.

2003-07-01

71

Observations of Volcanic SO2 and HCl from Aura MLS  

NASA Astrophysics Data System (ADS)

The Microwave Limb Sounder (MLS) on board the Aura satellite has been taking composition measurements of the Earth's upper troposphere, stratosphere and mesosphere for the past 5 years. During this time period, MLS has observed volcanic emissions from Manam, Anatahan, Soufriere Hills, Okmok, Kasatochi, Redoubt,and Sarychev eruptions. The eruptions from these volcanoes injected SO2 and HCl into the lower stratosphere. MLS makes vertically resolved measurements of these gases and therefore can determine the injection height of these volcanoes. We will provide a survey of the eruptions MLS has observed to date and compare results to SO2 columns seen by the Ozone Monitoring Instrument (OMI), also on the Aura satellite. Aura MLS however, can only make measurements along its orbit track twice daily which limits its usefulness for hazards detection or determining the amount of injected SO2. The utility of these measurements for hazard detection will be greatly enhanced in the next generation MLS instrument envisioned for the third tier decadal survey Global Atmospheric Composition Mission (GACM). The future mission will provide 50 km^2 near global coverage with 4--6 observations per day.

Read, W. G.; Froidevaux, L.; Santee, M. L.; Livesey, N. J.

2009-12-01

72

The Vibrational Spectra of Sulphuryl Fluoride, SO2F2 Sulphuryl Chloride Fluoride, SO2FC1, and Selenium Dioxide Difluoride, SO2F2.  

National Technical Information Service (NTIS)

The infra-red and Raman spectra of selenium dioxide difluoride, SeO2F2, are reported. The Raman spectrum of sulphuryl fluoride, SO2F2, was reinvestigated. The infra-red spectrum of SO2FC1 was measured. Vibrational assignments are given for SO2F2, So2FC1, ...

T. Birchall R. J. Gillespie

1966-01-01

73

Solubilities and diffusion of trace gases in cold sulfuric acid films  

Microsoft Academic Search

The well-known technique of gas chromatography was used to determine solubilities and liquid-phase diffusion coefficients of trace gases in a thin sulfuric acid film deposited in a fused silica column. Solubilities of SO2, NO2, and N2O4 and the diffusion coefficient of SO2 were measured in the temperature range 203–243K using sulfuric acid concentrations in the range of 39–83wt%. The results

Stefan Langenberg; Volker Proksch; Ulrich Schurath

1998-01-01

74

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...

75

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

Code of Federal Regulations, 2010 CFR

...atmosphere from any affected facility which combusts solid solvent refined coal (SRC-I) any gases that contain SO 2 in excess...and that burns 75 percent or more (by heat input) coal refuse on a 12-month rolling average basis,...

2009-07-01

76

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

Code of Federal Regulations, 2010 CFR

...atmosphere from any affected facility which combusts solid solvent refined coal (SRC-I) any gases that contain SO2 in excess of...and that burns 75 percent or more (by heat input) coal refuse on a 12-month rolling average basis,...

2010-07-01

77

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

78

Volcanic sulphur dioxide (SO2) in atmosphere from IASI data: analysis of SO2 amount and altitude for recent eruptions and volcanic degassing.  

NASA Astrophysics Data System (ADS)

Sulphur dioxide (SO2) is an important atmospheric constituent that plays a crucial role in many atmospheric processes. In the troposphere its 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. Volcanoes contribute about 1/3 to the tropospheric sulphur burden of which the majority is SO2. However, the absolute amount of the annual SO2 volcanic emission is both poorly constrained, and highly variable. The uncertainty in SO2 released arises for the stochastic nature of volcanic processes, very little or no surface monitoring of many volcanoes (so their contribution to annual emission is extremely uncertain) and from huge uncertainty in the contribution of volcanic sulphur emitted by quiescent (non-explosive) degassing. Volcanic SO2 retrievals from satellite data in the thermal infrared spectrum are based on two regions of SO2 absorption around 7.3 and 8.7 ?m. The strongest SO2 band is at 7.3 ?m and is contained in a strong water vapour (H2O) absorption band and is not very sensitive to emission from the surface and lower atmosphere. Above the lower atmosphere this band contains valuable information on the vertical profile of SO2. Fortunately differences between the H2O and SO2 emission spectra allow the signals from the two gases to be decoupled in high resolution measurements. The 8.7 ?m absorption feature is in an atmospheric window so it contains information on SO2 from throughout the column. The development of an SO2 retrieval algorithm that uses measurements from 1000 to 1200 cm-1 and from 1300 to 1410 cm-1 (the 7.3 and 8.7 ?m SO2 bands) made by the Infrared Atmospheric Sounding Instrument (IASI) (Carboni et al., 2012) on the MetOp satellite permits the quantification of SO2 amount and the estimate of the plume altitude. This retrieval scheme determines the column amount and effective altitude of the SO2 plume with high precision (up to 0.3 DU error in SO2 amount if the plume is near the tropopause) and can retrieve informations in the lower troposphere. There are several advantages of the IASI retrievals: (1) IASI makes measurements both day and night (so has global coverage every 12 hours), (2) the IASI retrieval does not assume plume height but retrieves an altitude for maximum SO2 amount (under the assumption that the vertical concentration of SO2 follows a Gaussian distribution). (3) IASI retrievals is not affected by underlying cloud (if the SO2 is within or below an ash or cloud layer its signal will be masked and the retrieval will underestimate the SO2 amount, in the case of ash this is a posteriori discernible by the cost function value) (4) A comprehensive error budget for every pixel is included in the retrieval. This is derived from an error covariance matrix that is based on the SO2-free climatology of the differences between the IASI and forward modelled spectra. In this work we present the results for recent volcanic eruptions and we will demonstrate the potential to monitor quiescent degassing from some volcano.

Carboni, Elisa; Grainger, Roy; Dudhia, Anu; Walker, Joanne; Siddans, Richard

2013-04-01

79

Detoxification of Dissolved SO2 (Bisulfite) by Terricolous Mosses  

Microsoft Academic Search

? Background and Aims The widespread calcifuge moss Pleurozium schreberi is moderately tolerant of SO2, whereas Rhytidiadelphus triquetrus is limited to calcareous soils in regions of the UK that were strongly affected by SO2 pollution in the 20th century. The proposition that tolerance of SO2 by these terricolous mosses depends on metabolic detoxification of dissolved bisulfite was investigated. ? Methods

BHAGAWAN BHARALI; JEFFREY W. BATES

2006-01-01

80

An Examination of NOx, SO2, and CO Emissions from East Texas Power Plants  

Microsoft Academic Search

Emissions from several East Texas power plants were measured from aircraft during the 2000 and 2006 Texas Air Quality Studies. One-second measurements were made of NOy, SO2, CO, and CO2 during these flights. NOy (total reactive nitrogen) is used as a proxy for power plant NOx (NO + NO2) emissions to account for any reactions that may have occurred between

J. Peischl; T. B. Ryerson; J. S. Holloway; K. C. Aikin; G. J. Frost; F. C. Fehsenfeld

2007-01-01

81

A reversible zwitterionic SO2-binding organic liquid  

SciTech Connect

As fossil fuel consumption continues, there is much attention being focused on capturing acid gas emissions from power plants. We have recently investigated SO2-binding organic liquids (SO2BOLs) as means to reversibly capture and release SO2 selectively over CO2.1 SO2BOLs are mixtures of tertiary amines and alcohols, which bind SO2 as liquid ammonium alkylsulfite salts. Tertiary amines selectively bind SO2 over CO2 because tertiary amines are basic enough to accept a proton from sulfurous and alkylsulfurous acids but not carbonic or alkylcarbonic acids. This is in contrast to other groups who absorb SO2 physically in ionic liquids2-4 or chemically absorb SO2 in organic systems5-7 or as irreversible aqueous bisulfite or sulfite salts.8-11 Our dual component SO2BOL ionic liquids can contain up to 47% SO2 by mass, have low specific heats, and can be desulfoxylated by heating to 90 ?C.1 We believed that a bifunctional tertiary alkanol amine would be able to capture SO2 comparable to our binary SO2BOL system. We present here the first reversible zwitterionic liquid produced from the reaction of SO2 with N,N-dibutylundecanolamine (DBUA). The SO2 is chemically bound through the alcohol moiety as an alkylsulfite, which we believe is stabilized by hydrogen bonding through the protonated amine portion of the molecule. Our recent interest in SO2BOLs led us to explore the possible reaction of aprotic alkanolamines with SO2 to form single-component SO2BOLs. A symbiotic pairing of the base and the alcohol on one molecule allows for a simple unimolecular system compared to the binary SO2BOL system. The bifunctional molecule also would have reduced volatility compared to tertiary amines due to increased hydrogen bonding from the alcohol moiety. To our knowledge there are few examples of zwitterionic liquids, and none of them have been shown to be reversible (polar to non-polar).12-14 Our first target molecule was N,N-dibutylundecanolamine because we envisioned long alkyl chains keeping the alkanolamine a liquid before and after exposure to SO2. N,N-dibutyldodecanolamine was synthesized in 88% isolated yield by refluxing dibutylamine and 11-bromoundecanol in ethanol.

Heldebrant, David J.; Koech, Phillip K.; Yonker, Clement R.

2010-01-05

82

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

83

Model Simulations of the Competing Climatic Effects of SO2 and CO2  

Microsoft Academic Search

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. Although there are large

Yoram J. Kaufman; Ming-Dah Chou

1993-01-01

84

Measurements of trace gas distributions using Long-path DOAS-Tomography during the motorway campaign BAB II: experimental setup and results for NO 2  

Microsoft Academic Search

The Tomographic Differential Optical Absorption Spectroscopy (Tom-DOAS) technique and results from a first application are presented. This novel technique serves to measure 2–3-dimensional concentration fields of different trace gases (e.g. NO2, SO2, ozone) in the planetary boundary layer on a small scale (100–10000m) by the use of multiple light paths. Ways to use telescopes, lamps, retroreflector arrays and spectrometers for

I. Pundt; K.-U. Mettendorf; T. Laepple; V. Knab; P. Xie; J. Lösch; C. v. Friedeburg; U. Platt; T. Wagner

2005-01-01

85

SO2 and CO2 removal from flue gas  

Microsoft Academic Search

The emission of green house gases is becoming of ever increasing worries to the international community. The fossil fuel consumption is still increasing and therefore the emission of the green house gases. Many uncertainties exist around the negative effects arising from large concentrations of green house gases in the atmosphere. To prevent possible negative effects in the future many countries

J. M. Alberts; J. H. C. Braber; H. C. A. Van Gastel; C. H. Tange; L. F. Zubeir

2006-01-01

86

Measurements of NO2-profiles during the CINDI campaign  

NASA Astrophysics Data System (ADS)

Satellite measurements of tropospheric constituents have advanced significantly over the last decade, now providing near global measurements of a number of species relevant in tropospheric chemistry (e.g. CO, NO2, HCHO, SO2, CHO.CHO). With improving spatial resolution, these data sets move towards air pollution monitoring and even air quality assessment. However, the integrating nature of this type of remote sensing measurements makes the link to in-situ data as they are usually provided by monitoring networks difficult. This is a problem for both vali-dation and interpretation of the satellite data. Multi-axis differential absorption spectroscopy (MAXDOAS) measurements can improve on this situation in several ways. Firstly, they can be used to provide directly the integrated tropospheric columns which are the quantity needed for validation. Secondly, they offer some vertical resolution, information which is needed in the retrieval of satellite data. Furthermore, their relatively high temporal resolution enables MAXDOAS to sample the diurnal cycle of trace gases which is not covered by satellite in-struments, yielding insight in the photochemistry of atmospheric pollutants. However, a good estimate on the accuracy of NO2 tropospheric columns and profiles for different atmospheric conditions (clouds/aerosols) and viewing geometries using the MAXDOAS technique is still missing. Here the CINDI campaign held in June to July 2009 in Cabauw provides the unique opportunity to compare and validate the MAXDOAS NO2-profiles with satellite, in-situ, NO2-lidar and NO2-sonde measurements. Furthermore it is possible to intercompare the different MAXDOAS results and finally come to recommendations for harmonization / standardization of instruments settings and retrieval algorithms. In addition to the real data a MAXDOAS model study has been initiated to identify more clearly the pros and cons for each method and to elaborate more clearly the general limitations of this technique. Results from both studies will be shown and discussed.

Wittrock, Folkard

87

Evaluation of ambient SO 2 measurement methods at roadside sites  

NASA Astrophysics Data System (ADS)

Accurate measurements of SO 2 at low ambient concentrations are needed in order to investigate the role of SO 2 in particle nucleation events and the long-term impact of reductions in sulfur emissions in recent decades. In this study, artifacts in SO 2 concentration measurements were investigated using two identical ion chromatography-based instruments (the Gas Particle Ion Chromatograph, GP-IC, Dionex Corporation) and two identical UV fluorescence-based SO 2 analyzers (the TECO 43CTL, an industry standard). The SO 2 concentration values measured with the GP-IC at roadside sites were compared with simultaneous side-by-side measurements made with the fluorescence analyzers. The SO 2 concentration measured with the GP-IC had an ˜30% negative calibration artifact. When the GP-ICs were calibrated using an improved procedure developed in the course of this study, only a ±5% difference from the TECO analyzers remained, except under high NO concentration conditions. The fluorescence analyzers exhibited a positive artifact under elevated NO concentration conditions. Sulfur oxidation ratios were calculated based on the GP-IC-measured SO 2 and SO 42- concentrations and used to help identify potential emission sources. The SO 2 concentrations measured with the GP-IC were also compared to data obtained from a National Air Pollution Surveillance (NAPS) speciation sampler equipped with a Na 2CO 3-coated denuder. Good correlation between SO 2 data from the two methods was seen during five months of measurement, but the GP-IC SO 2 data were ˜30% lower than the NAPS data. Deposition of SO 2 within an urban street canyon is discussed as a possible explanation for this difference.

Yao, Xiaohong; Lee, Colin J.; Evans, Greg J.; Chu, Amanda; Godri, Krystal J.; McGuire, Maygan L.; Ng, Andy C.; Whitelaw, Clarissa

2011-05-01

88

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

89

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

90

Investigation of the Limestone-SO2 Wet Scrubbing Process.  

National Technical Information Service (NTIS)

The wet lime-SO2 scrubbing process was investigated on a laboratory scale in support of full-scale prototype studies. The investigation consisted of laboratory scale experiments in the following areas: Measurement of the overall rate of uptake of SO2 in a...

R. W. Coutant R. H. Cherry H. Rosenberg J. Genco A. Levy

1969-01-01

91

STATUS OF DRY SO2 CONTROL SYSTEMS: FALL 1983  

EPA Science Inventory

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

92

Efficient SO2 capture by amine functionalized PEG.  

PubMed

Polyethylene glycols (PEGs) are a class of non-toxic, non-volatile, biocompatible, and widely available polymers. In this work, we synthesized N-ethyl-N-(2-(2-(2-methoxyethoxy)ethoxy)ethyl)-2-aminoethanol (EE3AE) that combines the properties of PEG and amines, and N-decyl-N-ethyl-2-aminoethanol (DEAE). Their performances to capture SO2 were studied at different temperatures, pressures, and absorption times. The interaction between the absorbents and SO2 were characterized by NMR and FTIR techniques. It was demonstrated that both EE3AE and DEAE could absorb SO2 efficiently, and there existed chemical and physical interactions between the absorbents and SO2. In particular, the absorption capacity of EE3AE could be as high as 1.09 g SO2 per g EE3AE at 1 atm. The absorption capacity of EE3AE was much larger than that of DEAE because the ether group in the EE3AE interacted with SO2 more strongly than the alkyl group in the DEAE. The SO2 absorbed by EE3AE could be stripped out by bubbling N2 or by applying a vacuum and the EE3AE could be reused. Moreover, both absorbents exhibited a high SO2-CO2 selectivity. PMID:24061406

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

2013-10-01

93

JAPANESE ACTIVITIES IN SO2 AND NOX CONTROL  

EPA Science Inventory

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

94

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

2013-05-16

95

Electron collision with sulfuryl chloride (SO2Cl2) molecule  

NASA Astrophysics Data System (ADS)

Absolute total cross section (TCS) for electron scattering from sulfuryl chloride (SO2Cl2) molecules was measured in a linear transmission experiment at energies ranging from 0.5 to 150 eV. The most distinct features found in the TCS are the deep minimum located near 1.8 eV and the broad enhancement peaked around 9.5 eV with a shoulder spanned between 3 and 5 eV. At intermediate energies, the present experimental TCS results agree well with our total cross-section estimations, based on calculations of elastic and ionization cross sections. In addition, the calculated total cross section for SO2F2 is reported. The results for e--SO2Cl2 collisions are compared, for the energy dependence and magnitude, with experimental and computed cross sections for other molecules (SO2F2, SO2ClF) comprising a sulfone group.

Szmytkowski, Czeslaw; Mozejko, Pawel; Kwitnewski, Stanislaw; Domaracka, Alicja; Ptasinska-Denga, Elzbieta

2006-06-01

96

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

Microsoft Academic Search

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

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

2004-01-01

97

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

98

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

Code of Federal Regulations, 2011 CFR

...approved by the Administrator: (1) The heat input (in mmBtu) used for calculating...The CAIR SO2 opt-in unit's baseline heat input determined under § 97.284(c); or (ii) The CAIR SO2 opt-in unit's heat input, as determined in...

2011-07-01

99

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

Code of Federal Regulations, 2011 CFR

...the following procedures: (1) The heat input (in mmBtu) used for calculating...The CAIR SO2 opt-in unit's baseline heat input determined under § 96.284(c); or (ii) The CAIR SO2 opt-in unit's heat input, as determined in...

2011-07-01

100

Highly efficient SO2 capture through tuning the interaction between anion-functionalized ionic liquids and SO2.  

PubMed

A strategy to improve SO(2) capture through tuning the electronegativity of the interaction site in ILs has been presented. Two types of imidazolium ionic liquids that include less electronegative sulfur or carbon sites were used for the capture of SO(2), which exhibit extremely highly available capacity, rapid absorption rate and excellent reversibility. PMID:23169110

Wang, Congmin; Zheng, Junjie; Cui, Guokai; Luo, Xiaoyan; Guo, Yan; Li, Haoran

2013-02-11

101

Thermodynamic state of SO2 on Io's surface  

NASA Astrophysics Data System (ADS)

It has been suggested that surface conditions on Io might be conducive to significant SO2 adsorption on sulfur or alkali sulfides. A number of spectroscopic arguments for and against the high abundance of a SO2 adsorbate (versus frost) on Io have been made. SO2 absorption isotherms on particulate sulfur are measured, and the question of SO2 adsorbate/ice is approached from a thermodynamic perspective. Because of formidable experimental difficulties, data were not obtained at the very low temperatures and P(SO2) characteristics of Io; however, data were obtained over a wide range of pressures and temperatures somewhat higher than Io's and extrapolated to Io surface conditions. Errors in estimating adsorptive capacity accrue through extrapolation of the adsorption isotherms; however, more significant is the addition of the solid SO2 equilibrium vapor pressure curve to the phase diagram. The formation of ice places a strict upper limit on adsorptive coverage at any temperature. The limit for Io based upon the data is calculated, and it is shown that no more than 0.014 monolayers of SO2 can adsorb on sulfur at Io temperatures. Given the assumption that sulfur forms the primary adsorbent on Io's surface, or the assumption that the adsorptive capacity of the other adsorbents is not substantially greater than that of sulfur, this explains the fact that the nu(1) + nu(3) band center position is in better agreement with that of frost than adsorbate.

Zent, A. P.; Fanale, F. P.

1987-05-01

102

Improving the accuracy of the SO2 camera  

NASA Astrophysics Data System (ADS)

The SO2 Camera is a novel technique to measure column densities and fluxes of SO2 emitted by volcanoes using solar radiation scattered in the atmosphere as a light source. The instrument is based on two interference band-pass filters and a UV-sensitive CCD sensor. A filter centered around 315 nm is used to measure the optical density of SO2in the plume, whereas a second filter, centered around 330 nm, corrects the effects of aerosol scattering and therefore makes the technique applicable to volcanic plumes containing aerosols. The ability to deliver spatially resolved images of volcanic SO2 distributions at a frame rate of the order of 1 Hz makes the SO2 camera a very promising technique for monitoring the evolution of volcanic plumes, the quantitative determination of SO2 emissions and flux measurements. This poster explains the measurement principle and how to evaluate data measured with the SO2camera. Several issues that can influence the measurement are addressed. For one, the change in light path through the stratosphere with changing solar zenith angle changes the spectral distribution measured on the earth's surface. As the absorption of SO2 is highly dependent on the wavelength of light, these changes can influence the measured column densities. Secondly, as the camera uses scattered solar radiation as a light source, we have to take radiative transfer effects in account. The path between the sun and the instrument is not fixed, as effects like multiple scattering or 'radiative dilution' can occur and lead to an underestimation or overestimation of the SO2 column density. Recommendations for correcting the individual effects during data analysis are given. Aside from the above-mentioned intrinsic effects, there are several choices in the technical setup of the SO2 camera which are discussed. A general description of the instrument's set-up and the camera control software are given. Finally, several measurement examples are shown and possibilities to combine SO2 camera measurements with other remote sensing techniques are explored. For example, a co-located DOAS system was used to accurately calibrate the SO2-camera data in real time and to correct for the radiative transfer effects.

Lübcke, Peter; Kern, Christoph; Vogel, Leif; Kick, Felix; Wöhrbach, Markus; Platt, Ulrich

2010-05-01

103

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

Code of Federal Regulations, 2010 CFR

...a 60-minute continuous period divided...time period. Integration of the instantaneous...the means of integration and any corrections...over a 24-hour continuous period divided...period. This integration may be...

2010-07-01

104

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

Code of Federal Regulations, 2010 CFR

...a 60-minute continuous period divided...time period. Integration of the instantaneous...the means of integration and any corrections...over a 24-hour continuous period divided...period. This integration may be...

2009-07-01

105

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

Microsoft Academic Search

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

Chatinai Chusai; Kasemsan Manomaiphiboon; Phirun Saiyasitpanich; Sarawut Thepanondh

2012-01-01

106

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

Microsoft Academic Search

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

Chatinai Chusai; Kasemsan Manomaiphiboon; Phirun Saiyasitpanich; Sarawut Thepanondh

2012-01-01

107

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

Microsoft Academic Search

The rate of calcareous stone degradation is to a significant extent controlled by their surface chemistry with SO2. Initial surface sulphite is converted to a harmful gypsum upon, e.g. NO2 catalysed oxidation. However, it has been observed by scanning electron microscopy that the lateral distributions of gypsum crystals differ between calcitic and dolomitic marbles. The first-principles density functional theory is

Katarina Malaga-Starzec; Itai Panas; Oliver Lindqvist

2004-01-01

108

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

109

Galapagos Islands Volcanic SO2 Emissions (1979-2009)  

NASA Astrophysics Data System (ADS)

Quantification of sulfur dioxide (SO2) released from the Galapagos Islands volcanoes is an essential part of interpreting their explosive and effusive eruptive activity. This is the first comprehensive study of Galapagos volcanic SO2 emissions (1979-2009), which has allowed us to evaluate their contribution to the global sulfur budget, assess the fate of the volcanic clouds, and interpret the connection between the emissions and eruptive dynamics. Galapagosian eruptions typically produce effusive SO2 clouds through nearly constant emissions over the course of several days. We used measurements from the Total Ozone Mapping Spectrometer (TOMS) satellite instruments to quantify SO2 emissions between 1979 and 2005. Daily SO2 emission rates are traditionally estimated by analyzing individual satellite images. Analyses of polar-orbiting satellite data for effusive eruptions, however, can underestimate total SO2 emissions because the instantaneous satellite images contain a spectrum of SO2 plume ages, from freshly emitted to aged (erupted 24 hours or more earlier and dispersing). Therefore, a new method is used in this study, involving extrapolation between once-daily TOMS data acquisitions to more accurately estimate SO2 emissions from the Galapagosian eruptions. Comparing our results to current global volcanic sulfur budget studies, all known Galapagos eruptions between 1979 and 1997 produced a total SO2 emission of 5 Mt +/- 2 Mt, equivalent to roughly 2% of the global volcanic sulfur budget. However, the SO2 emissions may be significant on a regional scale and their effects on the environment and ecosystem of the islands merit further investigation. One of the most explosive of these volcanoes is Sierra Negra, which produced almost half of the total estimated SO2 (2 Mt) during a single eruption (in 1979) in this time period. The Galapagos volcanic clouds are typically entrained into the lower troposphere and have a 60-95% decay rate, with most SO2 clouds losing ~70% mass within a 24 hour period. Of the eight Galapagos eruptions studied so far, SO2 emission patterns from the 1979 Sierra Negra and 1982 Wolf eruptions suggest that the eruption mechanism for these two eruptions is a release of elastic strain within their individual magma chambers. The remaining eruptions have SO2 emission patterns that would suggest different eruption mechanisms. More recently, eruptions occurred at Sierra Negra in 2005, Cerro Azul in 1998 and 2008, and Fernandina in 2009. We will present new SO2 emission data for these eruptions using the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, which has better spectral and spatial resolution than TOMS. With these new OMI data, we will reassess the contribution of the Galapagos SO2 emissions to the global sulfur budget, as well as evaluate the eruption mechanisms in relation to previous activity.

Head, E. M.; Carn, S. A.; Bluth, G. J.

2010-12-01

110

Central Arctic Atmospheric SO2 pollution from smelters: Airborne detection and Arctic Haze formation  

NASA Astrophysics Data System (ADS)

Arctic Haze represents a dramatic manifestation of anthropogenic pollution of a remote and previously pristine atmospheric environment, which presently experiences faster climate warming than any other region on the planet. Arctic haze influences visibility, ecosystems, and may contribute to Arctic climate warming. In spring, Arctic Haze occupies large parts of the Arctic lower troposphere, the so called Arctic Dome. The most abundant Arctic Haze component is sulphate, which was previously thought to stem preferably from Extra-Arctic anthropogenic pollution sources. However, recent model simulations suggest that sulphate particle transport into the Arctic Dome is severely hindered. During the recent POLAR YEAR 2007/2008, in 2007, we have made the first Central Arctic SO2 measurements with high vertical and horizontal resolution and detected SO2 rich pollution plumes in the entire troposphere height range up to 9000 m. Below 2000 m, inside the Arctic Dome, these plumes were most pronounced and stemmed preferably from a giant Ni-Cu smelter complex, located in the Siberian sector of the Arctic Dome, near the city Norilsk, at a distance of 2100 km from our measurement region. Our measurements and accompanying model simulations indicate that SO2 emitted by that smelter complex represents a mayor if not the dominant precursor of Arctic Dome cloud condensation nuclei and haze particles. Along with SO2, were measured aerosol particles and additional trace gases including also gas-phase NOy (sum of reactive nitrogen gases). Importantly, the abundance ratio R=SO2/NOy is quite different for different SO2 source types (about 1-2 for fossil fuel combustion, <0.1 for bio mass burning, and about 40 for Ni/Cu smelting) and therefore serves as an SO2-source marker. In addition to our air craft measurements, we have made accompanying model simulations of pollutant transport and aerosol formation and growth. Our air craft measurements were part of the ASTAR 2007 (ASTAR=Arctic Study of Tropospheric Aerosols, Clouds, and Radiation) campaign and took place in March/April 2007 (during the recent "International Polar Research Year") aboard the German research air craft FALCON, mostly in the vicinity of Spitsbergen about 2100 km away from Norilsk. Atmospheric SO2 was measured on 7 Central Arctic FALCON flights at altitudes up to 10000 m in the geographic region between approximately 74-83 degrees North and 10-20 degrees East. On the FALCON flights, Arctic Haze was often observed as a dark coloured band against the horizon. During each of the 7 Central Arctic FALCON flights, stratified SO2 rich pollution plumes, with elevated SO2 mole fractions of 300-6000 ppt, have been detected below 2000 m. In comparison, measured atmospheric background SO2 mole fractions were usually below about 40 ppt. In addition, numerous SO2 rich pollution plumes were detected in almost the entire altitude range covered.

Arnold, F.; Nau, R.; Jurkat, T.; Schlager, H.; Minikin, A.; Dörnbrack, A.; Pirjola, L.; Stohl, A.

2009-04-01

111

Use of sulfate reducing cell suspension bioreactors for the treatment of SO2 rich flue gases.  

PubMed

This paper describes a novel bioscrubber concept for biological flue gas desulfurization, based on the recycling of a cell suspension of sulfite/sulfate reducing bacteria between a scrubber and a sulfite/sulfate reducing hydrogen fed bioreactor. Hydrogen metabolism in sulfite/sulfate reducing cell suspensions was investigated using batch activity tests and by operating a completely stirred tank reactor (CSTR). The maximum specific hydrogenotrophic sulfite/sulfate reduction rate increased with 10% and 300%, respectively, by crushing granular inoculum sludge and by cultivation of this sludge as cell suspension in a CSTR. Operation of a sulfite fed CSTR (hydraulic retention time 4 days; pH 7.0; sulfite loading rate 0.5-1.5 g SO3(2-) l(-1) d(-1)) with hydrogen as electron donor showed that high (up to 1.6 g l(-1)) H2S concentrations can be obtained within 10 days of operation. H2S inhibition, however, limited the sulfite reducing capacity of the CSTR. Methane production by the cell suspension disappeared within 20 days reactor operation. The outcompetition of methanogens in excess of H2 can be attributed to CO2 limitation and/or to sulfite or sulfide toxicity. The use of cell suspensions opens perspectives for monolith or packed bed reactor configurations, which have a much lower pressure drop compared to air lift reactors, to supply H2 to sulfite/sulfate reducing bioreactors. PMID:12889613

Lens, P N L; Gastesi, R; Lettinga, G

2003-06-01

112

Determination of hydrogen sulfide in fermentation broths containing SO 2 .  

PubMed

A procedure for the determination of hydrogen sulfide in fermentation broths containing up to 100 mug of SO(2) per ml is described. The method involves the sparging of H(2)S from the broth into a cadmium hydroxide absorption solution, the formation of methylene blue from the absorbed sulfide, and the measuring of this color spectrophotometrically. The use of cadmium hydroxide instead of zinc acetate, the common absorbent, substantially reduced the interference of SO(2) with the analysis. PMID:5111300

Acree, T E; Sonoff, E P; Splittstoesser, D F

1971-07-01

113

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

114

Experimental investigation of SO 2 uptake in snow  

Microsoft Academic Search

We conducted a series of bench-top experiments to examine accumulation of acidity in temperate snowpacks due to the deposition of SO2. To achieve this, SO2 at concentrations of 45–85 ppbv was allowed to diffuse into containers of snow at 0°C for varying lengths of time, from 6 to 46h. Depth profiles of dissolved total sulfur (S(IV)+S(VI)) in the snow were

Jungyill Choi; Martha H. Conklin; Roger C. Bales; Richard A. Sommerfeld

2000-01-01

115

Volcanic SO2 plume forecasts based on UV satellite observations  

NASA Astrophysics Data System (ADS)

We present how SO2 observations from satellites were used to facilitate forecasts of volcanic sulphur dioxide (SO2) plumes. Volcanic SO2 is often co-located with volcanic ash and can in many cases be considered as a proxy for volcanic ash. Satellite retrievals of SO2 total columns from GOME-2, OMI and SCIAMACHY for the eruptions of Grímsvötn and Eyjafjallajökull in May 2011 and 2010 were inter-compared and used to (i) estimate source strength and injection height and (ii) to provide SO2 initial conditions for forecasts by means of data assimilation. The forecasts were carried out as an activity within the European MACC project (Monitoring of atmospheric composition and climate). MACC builds and runs a near-real-time system for the forecast of global atmospheric composition using the integrated forecast system of ECMWF. Our study found that OMI retrievals had the highest maximum values and that GOME-2 observations provided the most complete spatial coverage. Basic estimates of plume parameters were inferred from the satellite retrievals by finding the best match with an ensemble of plume forecasts injected at different levels. Further, the SO2 retrievals were assimilated with ECMWF's 4D-VAR algorithm to obtain initial conditions for the plume forecasts. These initialized plume forecasts were also used to validate the consistency of the satellite observations for consecutive days. The Grímsvötn plume could mostly be predicted by the initialized forecasts, whereas the forecasts of the Eyjafjallajökull plume benefited more from the source term estimate.

Flemming, J.; Inness, A.

2012-04-01

116

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

117

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

118

Efficient Low-Temperature Oxidation of Carbon-Cluster Anions by SO2  

NASA Astrophysics Data System (ADS)

Carbon-cluster anions, CN^-, are very reactive toward SO2 (sticking probability of 0.012 ± 0.005 for C27^- at 25 ^oC), in contrast to their inertness toward other common atmospheric gases and pollutants. In flow-reactor experiments at ambient temperature and near atmospheric pressure, primary adsorption of SO2 by the carbon cluster anions, N = 4 -- 60, yields CNSO2^- or CN-1S^-. The inferred elimination of neutral CO2 is also detected as meta-stable decay in collision-induced dissociation. At higher temperatures, the reaction of SO2 with nascent carbon clusters yields CN-1SO^- as well as undetected CO. Such carbon clusters are formed in sooting flames and may act as nuclei for the formation of primary soot particles, and serve as models for the local structural features of active soot particle sites for black-carbon soot. The facile generation of reactive carbon-sulfide and --sulfinate units may therefore have implications for understanding the health and environmental effects attributed to the coincidence of soot and SO2.

Leavitt, Andrew; Wywras, Richard; Wallace, William; Serrano, Daniel; Arredondo, Melissa; Leslie, Logan; Khan, Farooq; Whetten, Robert

2006-03-01

119

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

120

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

121

NO2 Photodissociation Dynamics.  

National Technical Information Service (NTIS)

The studies carried out under the present contract have all involved investigations of the photophysics and photochemistry of two nitrogen oxide molecules, NO and NO2. As well as being intrinsically interesting, these molecules are important from the poin...

T. G. Slanger

1989-01-01

122

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

123

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

124

Model Simulations of the Competing Climatic Effects of SO2 and CO2.  

NASA Astrophysics Data System (ADS)

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. Although there are large gaps in our knowledge of the atmospheric sources and sinks of sulfate aerosol, it is possible to reach some general conclusions. Using a conservative approach, results show that the cooling induced by the SO2 emission can presently counteract 50% 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% for the Intergovernmental Panel on Climate Change (IPCC) business as usual (BAU) scenario and 0.2°C or 20% for scenario D (for a slow pace of fossil fuel burning). The hypothesis is examined that the different responses between the Northern Hemisphere (NH) and the Southern Hemisphere (SH) can be used to validate the presence of the SO2-induced cooling. Despite the fact that most of the SO2-induced cooling takes place in the Northern Hemispheric continents, the model-predicted difference in the temperature response between the NH and the SH of 0.2°C in 1980 is expected to remain about the same at least until 2060. This result is a combined effect of the much faster response of the continents than the oceans and of the larger forcing due to CO2 than due to the SO2. The climatic response to a complete filtering of SO2 from the emission products in order to reduce acid rain is also examined. The result is a warming surge of 0.4°C in the first few years after the elimination of the SO2 emission.

Kaufman, Yoram J.; Chou, Ming-Dah

1993-07-01

125

Monitoring of volcanic SO2 emissions using the GOME-2 satellite instrument  

NASA Astrophysics Data System (ADS)

Volcanic eruptions are a major hazard to the local population near large volcanoes and to aviation, they also play an important role in global climate change. Atmospheric SO2 is an important indicator for volcanic eruptions and volcanic activity like passive degassing. Space based atmospheric sensors like GOME-2 on MetOp and OMI on EOS-Aura make it possible to detect the emissions of volcanic SO2 in near-real time (NRT) and monitor volcanic activity and eruptions on a global scale. This is important as satellites are often the first, and sometimes the only, source of information on volcanoes in remote locations because ground based monitoring of volcanic gases with MAX-DOAS, COSPEC or direct gas measurements is carried out only for a limited number of volcanoes. The GOME-2 instrument on the satellite MetOp provides operational measurements of the SO2 columns with a spatial resolution of 80x40 km² and a global coverage within about one day. Volcanic sulfur dioxide emissions are determined from solar backscatter measurements in the ultra-violet spectral range between 315 - 326 nm, applying the Differential Optical Absorption Spectroscopy (DOAS) method. This retrieval technique uses the high spectral resolution of the instruments to determine the total column density of SO2. With GOME-2 it is possible to detect and track volcanic eruption plumes in near-real time (NRT), which makes it a valuable tool for aviation warning, as SO2 can be used as a tracer for volcanic eruption plumes that are hazardous to aircraft. The ability to monitor changes in volcanic degassing behavior is of great importance for early warning of volcanic activity, as large increases in SO2 fluxes are often an indicator for new episodes of volcanic unrest. In this contribution, we present exemplary results of volcanic SO2 retrieved from GOME-2 data using the Differential Optical Absorption Spectroscopy method, including analyses for recent volcanic eruptions and volcanic degassing events detected by GOME-2. We will present the use of the operational GOME-2 SO2 data for early warning of volcanic hazards within the Aviation Control Support Service and within a new Volcano Fast Response System (Exupéry) that includes both ground-based and satellite observations.

Rix, M.; Valks, P.; Hao, N.; Erbertseder, T.

2009-04-01

126

Controlling SO2 emissions in the roasting of gold concentrate  

NASA Astrophysics Data System (ADS)

Acid pressure oxidation is generally believed to be the most effective pretreatment for refractory sulfide gold ores and concentrates, although it is ineffective for some ores. For such ores and concentrates (usually those containing both carbonaceous and sulfide materials), roasting remains the most effective pretreatment before cyanidation. However, the serious environmental damage that could result from the emission of SO2 and As2O3 makes roasting an unattractive pretreatment step. In an effort to develop a technique having lower SO2 emissions, a lime agglomeration roast (LAR) pretreatment process was investigated. The technique involves the agglomeration of calcium-based SO2 sorbent with the refractory ore or concentrate before roasting. The results of the LAR pretreatment followed by cyanidation indicate that up to 95 percent of the sulfur dioxide can be captured and more than 90 percent gold extraction can be achieved.

Nyavor, Kafui; Egiebor, Nosa O.

1991-12-01

127

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

128

CO 2 and SO 2 uptake by oil shale ashes  

Microsoft Academic Search

In the present research, CO2 and SO2 binding ability of different oil shale ashes and the effect of pre-treatment (grinding, preceding calcination) of these ashes\\u000a on their binding properties and kinetics was studied using thermogravimetric, SEM, X-ray, and energy dispersive X-ray analysis\\u000a methods. It was shown that at 700 °C, 0.03–0.28 mmol of CO2 or 0.16–0.47 mmol of SO2 was bound by 100 mg

Andres Trikkel; Merli Keelmann; Tiit Kaljuvee; Rein Kuusik

2010-01-01

129

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

130

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...

131

COMBUSTION ENGINEERING'S FURNACE SORBENT INJECTION PROGRAMS FOR SO2 CONTROL  

EPA Science Inventory

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

132

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/...

133

Forecasting Ambient Air SO2 Concentrations Using Artificial Neural Networks  

Microsoft Academic Search

An Artificial Neural Networks (ANNs) model is constructed to forecast SO2 concentrations in Izmir air. The model uses meteorological variables (wind speed and temperature) and measured particulate matter concentrations as input variables. The correlation coefficient between observed and forecasted concentrations is 0.94 for the network that uses all three variables as input parameters. The root mean square error value of

Sait C. Sofuoglu; Aysun Sofuoglu; Savas Birgili; Gokmen Tayfur

2006-01-01

134

Ambient air SO2 patterns in 6 European cities  

NASA Astrophysics Data System (ADS)

An analysis of the hourly SO2 pollution patterns with time can be a useful tool for policy makers and stakeholders in developing more effective local policies in relation to air quality as it facilitates a deeper understanding of concentrations and potential source apportionment.

Henschel, Susann; Querol, Xavier; Atkinson, Richard; Pandolfi, Marco; Zeka, Ariana; Le Tertre, Alain; Analitis, Antonis; Katsouyanni, Klea; Chanel, Olivier; Pascal, Mathilde; Bouland, Catherine; Haluza, Daniela; Medina, Sylvia; Goodman, Patrick G.

2013-11-01

135

Monitoring of SO2 emissions from industry by passive DOAS  

Microsoft Academic Search

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

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

2005-01-01

136

Effect of UV scattering on SO2 emission rate measurements  

Microsoft Academic Search

We report the quantitative evaluation of the UV scattering effect on the SO2 emission rate measurement by the compact UV spectrometer system. Plume spectra were obtained simultaneously at three measuring points with different distance to the volcanic plume. The apparent absorbance decreases with increasing distance to the plume and the attenuation becomes stronger at shorter wavelength bands. In addition, the

Takehiko Mori; Toshiya Mori; Kohei Kazahaya; Michiko Ohwada; Jun'ichi Hirabayashi; Shin Yoshikawa

2006-01-01

137

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...

138

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...

139

COMPARISON OF HISTORIC SO2 AND NOX EMISSION DATA SETS  

EPA Science Inventory

The report gives results of a comparison of historic SO2 and NOx emission data sets. During the past few years, several research projects have been conducted to reconstruct historic air pollution emission trends in the U.S. The report compares in detail the emission estimates and...

140

BENCH SCALE STUDIES OF LIMESTONE INJECTION FOR SO2 CONTROL  

EPA Science Inventory

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

141

SO2 AND NOX CONTROL TECHNOLOGY RESEARCH, DEVELOPMENT, AND DEMONSTRATION  

EPA Science Inventory

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

142

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...

143

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 ...

144

Investigating Statospheric Loss Rates of Volcanic SO2  

Microsoft Academic Search

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

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

2002-01-01

145

Interaction between SO 2 and submicron atmospheric particles  

Microsoft Academic Search

In the atmosphere, oxidation of sulfur dioxide (SO2) to sulfate may occur in the gas phase, in cloud or fog droplets, or in the aerosol phase on the surface or inside aerosol particles. While aerosol phase reactions have been studied in the case of supermicron sea-salt and crustal particles, very few investigations regarding submicron particles are available. In this paper,

Veli-Matti Kerminen; Liisa Pirjola; Michael Boy; Arkke Eskola; Kimmo Teinilä; Lauri Laakso; Ari Asmi; Jukka Hienola; Antti Lauri; Veera Vainio; Kari Lehtinen; Markku Kulmala

2000-01-01

146

A sensitive search for SO 2 in the martian atmosphere: Implications for seepage and origin of methane  

NASA Astrophysics Data System (ADS)

Mars was observed near the peak of the strongest SO 2 band at 1364-1373 cm -1 with resolving power of 77,000 using the Texas Echelon Cross Echelle Spectrograph on the NASA Infrared Telescope Facility. The observation covered the Tharsis volcano region which may be preferable to search for SO 2. The spectrum shows absorption lines of three CO 2 isotopomers and three H 2O isotopomers. The water vapor abundance derived from the HDO lines assuming D/H = 5.5 times the terrestrial value is 12±1.0 pr. ?m, in agreement with the simultaneous MGS/TES observations of 14 pr. ?m at the latitudes (50° S to 10° N) of our observation. Summing of spectral intervals at the expected positions of sixteen SO 2 lines puts a 2 ? upper limit on SO 2 of 1 ppb. SO 2 may be emitted into the martian atmosphere by seepage and is removed by three-body reactions with OH and O. The SO 2 lifetime, 2 years, is longer than the global mixing time 0.5 year, so SO 2 should be rather uniformly distributed across Mars. Seepage of SO 2 is less than 15,000 tons per year on Mars which is smaller than the volcanic production of SO 2 on the Earth by a factor of 700. Because CH 4/SO 2 is typically 10 -4-10 -3 in volcanic gases on the Earth, our results show seepage is unlikely to be the source of the recently discovered methane on Mars and therefore strengthen its biogenic origin.

Krasnopolsky, Vladimir A.

2005-11-01

147

Symphony No 2: \\  

Microsoft Academic Search

Symphony No. 2 (The Revelation) intended to be a nine movement symphonic poem when fully completed, is loosely based on the events and imagery revealed in the Book of Revelation. Three movements completed to fulfill the requirement for the D.M.A. are: (1) prologue: The crucifixion of Christ; (2) Movement II: The breaking of the seven seals and the sounding of

Cheong Leong Chuah

1994-01-01

148

Variabilities and inter-relation among Ozone, CO, NOy and SO2 over the central Himalayas  

NASA Astrophysics Data System (ADS)

Trace gases play vital roles in the tropospheric chemistry, air quality degradation and climate change. Despite this, measurements of the key trace gases are sparse over the Indian region, particularly over the Northern India including Indo-Gangetic Plain (IGP), where elevated levels of pollution loadings has been observed in different satellite based studies. In view of this, measurements of ozone, CO, NOy, and SO2 are initiated at a high altitude site (Nainital; 29.37oN, 79.45oE, 1958 m amsl) in the central Himalayas. Diurnal variations in ozone do not show a daytime build up, indicating that photochemistry plays only a minor role in ozone variations at Nainital. While, in contrast, CO, NOy and SO2 generally show higher levels during daytime and lower levels during nighttime. Such diurnal variations are attributed to the boundary layer evolution and mixing processes. Seasonal variations in ozone, CO, NOy and SO2 at Nainital are characterized by higher levels during spring unlike hydrocarbons, which show a late autumn and early winter maxima. Lowest levels of all these species are observed during summer/monsoon period due to arrival of clean marine air mass and extensive rainfall. The correlation among different species is used to gain insight into the sources of these species along with transport and chemical characteristics of air masses. A correlation analysis of ozone observations at Nainital with those at a nearby low altitude site in the IGP suggests that emissions and photochemistry of the IGP region influences the air quality of Himalayan region via boundary layer mixing process particularly during noon hours of spring. Chemical box model simulations are being used to study the observed variations in ozone and precursors and their inter-relation. Detailed analysis is in progress and will be discussed during the presentation.

Sarangi, Tapaswini; Ojha, Narendra; Lal, Shyam; Naja, Manish; Kumar, Rajesh; Venkataramani, S.; Chandola, H. C.

2012-07-01

149

Atmospheric effects on winter SO 2 pollution in Lanzhou, China  

Microsoft Academic Search

Lanzhou is one of the most polluted cities in China. Sulfur dioxide (SO2) concentrations have shown evident seasonal variability. Pollution was generally within the second-level criterion (<0.15 mg m?3) in spring, summer, and fall but was much higher than the second-level criterion and sometimes reaches mid-level pollution (API>200) in winter. Meteorological conditions (low winds, stable stratification) were found to be important

Peter C. Chu; Yuchun Chen; Shihua Lu

2008-01-01

150

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

151

On the absolute calibration of SO2 cameras  

USGS Publications Warehouse

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

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

2013-01-01

152

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

153

SO2 Radiative Forcing on Late Noachian Mars  

NASA Astrophysics Data System (ADS)

Data recently returned from Mars suggest that sulfur may have played a significant role in the planet's evolution. We present results from a model for sulfur delivery to the Martian surface with a special focus on the radiative transfer implications of sulfur volatiles introduced to the late Noachian atmosphere during Tharsis loading. We obtain a high sulfur solubility in Martian mantle melts, approximately 1400 ppm, using the Gusev Crater basalt composition and a batch melting model. We specifically explore two modeled volumes, a lower bound of 1500 km3 and an upper bound of 60,000 km3, for lava rapidly emplaced by Tharsis-radial dikes to ascertain the potential magnitude of degassing pulses of SO2. With conservative model assumptions and a faint young Sun approximation (75% present-day luminosity), we investigate the additional atmospheric heating due to solar radiation associated with these SO2 influxes in both 50 mb and 500 mb CO2 background atmospheres using Mars-WRF, a three-dimensional GCM adapted for Martian conditions. Results indicate an additional 5-20 K greenhouse warming effect from SO2 absorption in wavelength windows complimentary to CO2, and localized conditions conducive to the presence of transient liquid water. It appears that potent, periodic warming events associated with volcanic degassing on early Mars may be an important factor in understanding both the prevalence of sulfates on the planet's surface today as well as the geologic evidence for near-surface liquid water or brine in the distant past.

Mischna, Michael A.; Johnson, S. S.; Zuber, M. T.; Grove, T. L.

2006-09-01

154

UV-DOAS for determination of NOx to HNO3\\/NO3- and SO2 to H2SO4\\/SO42-transformation rates  

Microsoft Academic Search

This research employs UV-DOAS to log ambient atmospheric measurements of criteria pollutants and to gather data specifically for determining transformation rates. Species of concern include oxides of nitrogen (NO + NO2 = NOx) and sulfur dioxide (SO2). Combustion sources such as coal fired power plants continuously emit NOx and SO2, which enter the atmosphere and become dispersed and transformed, resulting

Kerstin L. Kenty

2002-01-01

155

Reactivityof oil shale ashes in the binding of SO 2  

Microsoft Academic Search

The extensive use of fossil fuels in energy production causes serious\\u000a pollution of atmosphere with SO2, CO2,\\u000a NOx, etc. In Estonia the electricity production is\\u000a based mainly on the pulverized firing (PF) of low-grade local fuel –\\u000a Estonian oil shale (EOS) which is characterized by a low calorific value (~9\\u000a MJ kg–1) and a high content of mineral matter\\u000a (65–70%)

T. Kaljuvee; M. Toom; A. Trikkel; R. Kuusik

2007-01-01

156

Soil acidification in China: Is controlling SO2 emissions enough?  

NASA Astrophysics Data System (ADS)

Facing challenges of regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector, in order to achieve the national goal of 10% reduction in sulfur dioxide (SO2) emissions from 2005 to 2010. In this study, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO2, oxides of nitrogen (NOX), particulate matter (PM), and ammonia (NH3) in 2005 were estimated to be 30.7, 19.6, 31.3 and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO2 and PM emissions, while those of NOX and NH3 will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur deposition (indicated by CLmax(S)) was exceeded in 28% of the country’s territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (combining effects of eutrophication and acidification, indicated by CL(N)) will double from 2005 to 2020 due to increased NOX and NH3 emissions. Combining the acidification effects of S and N(indicated by CL(S)), the benefits of SO2 reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (both NOX and NH3) and deposition will be a major challenge to China, requiring both policy development and technology investments. To mitigate acidification in the future, China needs a multi-pollutant control strategy that integrates measures to reduce S, N and PM. Exceedances of critical loads for acidification and nutrient nitrogen in 2005, 2010, and 2020. Critical load exceedance in 2005, 2010 and 2020

Zhao, Y.; Duan, L.; Xing, J.; Larssen, T.; Nielsen, C. P.; Hao, J.

2009-12-01

157

Exactly Solvable Central Force Potentials and so(2,1)  

NASA Astrophysics Data System (ADS)

We find the energy eigenvalues and eigenfunctions of four central force potentials: the Coulomb potential, the modified Coulomb potential (Ar-1 + Br-2), the 3D isotropic harmonic oscillator, and the Davidson potential (the modified 3D isotropic oscillator, Ar^2 + Br-2), using^1 so(2,1) and it's similarities to so(3) and angular momentum. We also prove that these are the only four central force potentials which this method can solve exactly. This serves as an excellent example of how a given algebraic structure, once established, can elegantly solve multiple problems with little extra work. ^1 J. Cizek and J. Paldus, Int. J. Quant. Chem. 12, 875 (1977)

Cooke, Teman H.; Wood, John L.

2000-11-01

158

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

159

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

160

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

2011-03-07

161

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

2012-04-04

162

Electrochemical Methods for Cleansing of H2S and SO2 in Industrial and Natural Contaminated Waters  

NASA Astrophysics Data System (ADS)

Hydrogen sulfide and sulfur dioxide are hazardous to the environment pollutants. They are contained in industrial and utility waste gases and waters as well as in some natural lakes and Seas. The present paper is a review of our studies on the electrochemical oxidation-reduction processes for SO2 and H2S cleansing by their oxidation with oxygen contained in the air. An innovative Carbon-Teflon structure of the electrodes (membranes) allows for the simultaneous electro-catalytic reactions of SO2, H2S and oxygen, proceeding on dispersed micro-galvanic elements, based on their chemical affinity without external power application. The physical model of electrochemical reactions in Carbon-Teflon electrodes is presented. The electrochemical nature of the processes is revealed using the additive principle. The results are used for development of processes for purification of SO2 and H2S from industrial gasses and waters. The major relations describing the processes, namely the impacts of sulfur dioxide and sulfuric acid concentrations have been studied. The revealed simplified expressions facilitate the performance estimation of an innovative process for SO2 cleansing in waste gases, labeled ELCOX.

Petrov, Konstantin

163

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

2012-12-03

164

Laboratory detection of protonated SO2 in two isomeric forms  

NASA Astrophysics Data System (ADS)

By means of Fabry-Pérot Fourier transform microwave spectroscopy, the rotational spectrum of protonated sulfur dioxide in two distinct isomeric forms, a cis- and a trans-geometry, is reported. The search for both isomers was based on theoretical structures obtained at the CCSD(T)/cc-pwCVQZ level of theory corrected for zero-point vibrational effects. At a similarly high level of theory, the cis-isomer is calculated to be the global minimum on the potential energy surface, but the trans-isomer is predicted to lie only a few kcal/mol higher in energy. A total of seven lines, including a- and b-type transitions, has been observed for both isomers, and precise rotational constants have been derived. Because sulfur dioxide, SO2, is a widespread and very abundant astronomical species, and because it possesses a large proton affinity, HOSO+ is an excellent candidate for radioastronomical detection.

Lattanzi, Valerio; Thaddeus, Patrick; McCarthy, Michael C.; Thorwirth, Sven

2010-11-01

165

Spectroscopic study of the photofixation of SO2 on anatase TiO2 thin films and their oleophobic properties.  

PubMed

Photoinduced SO(2) fixation on anatase TiO(2) films was studied by in situ Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The TiO(2) films were prepared by reactive DC magnetron sputtering and were subsequently exposed to 50 ppm SO(2) gas mixed in synthetic air and irradiated with UV light at substrate temperatures between 298 and 673 K. Simultaneous UV irradiation and SO(2) exposure between 373 and 523 K resulted in significant sulfur (S) deposits on crystalline TiO(2) films as determined by XPS, whereas amorphous films contained negligible amounts of S. At substrate temperatures above 523 K, the S deposits readily desorbed from TiO(2). The oxidation state of sulfur successively changed from S(4+) for SO(2) adsorbed on crystalline TiO(2) films at room temperature without irradiation to S(6+) for films exposed to SO(2) at elevated temperatures with simultaneous irradiation. In situ FTIR was used to monitor the temporal evolution of the photoinduced surface reaction products formed on the TiO(2) surfaces. It is shown that band gap excitation of TiO(2) results in photoinduced oxidation of SO(2), which at elevated temperatures become coordinated to the TiO(2) lattice through interactions with O vacancies and form sulfite and sulfate surface species. These species makes the surface acidic, which is manifested in nondetectable adherence of stearic acid to the modified surface. The modified films show good chemical stability as evidenced by sonication and repeated recycling of the films. The results suggest a new method to functionalize wide band gap oxide surfaces by means of photoinduced reactions in reactive gases at elevated substrate temperatures. In the case of anatase TiO(2) in reactive SO(2) gas, we here show that such functionalization yields surfaces with excellent oleophobic properties, as probed by adhesion of stearic acid. PMID:22204641

Topalian, Z; Niklasson, G A; Granqvist, C G; Österlund, L

2012-01-26

166

NO2 Detection Using Microcantilever Based Potentiometry  

PubMed Central

A highly sensitive and novel sensor platform for gases and volatile chemicals using microcantilever based potentiometry is reported. A resonant cantilever is used to detect the changes in surface work functions of functionalized substrates caused by adsorption of target gas molecules. Surface work function (SWF) changes were measured for different functionalization layers made of transition metal oxide thin films with the flow of NO2. The rate of change in SWF for In2O3 and SnO2 were found to be ?80 and ?100 ?V/sec, respectively, for 70 ppm NO2. A sensitivity of 64 ?V/sec for SWF change was also found for 70 ppm NO2 concentration for isolated clusters of ZnO nanowires, indicating that this technique is applicable even for nano-clusters of sensing materials where amperometric detection is impossible due to material discontinuity. NO2 detection as low as 400 ppb was possible using highly insulating In2O3 and SnO2 thin films (resistivity > 1 T?/?. Two different forms of nano scale graphite were compared with the transition oxide based functionalization layer for sensing sub-ppm NO2 sensing. It was observed that nanostructured graphite (NG) shows much higher sensitivity and lower response time than transition metal oxides.

Qazi, Muhammad; Koley, Goutam

2008-01-01

167

Assessing the effect of SO 2 emission changes on visibility  

NASA Astrophysics Data System (ADS)

During the 1970s the effect of acid rain on the environment became a growing concern to scientists, public policy officials, interest groups, and the general population. The United States' Congress mandated a 10-year study, National Acid Precipitation Assessment Program (NAPAP), to examine the relationship between acid rain related emissions and environmental effects including visibility. It was found that averaging over both space and time (1 yr) that a 21 % improvement in visibility could be expected from a 10-million ton reduction in SOz emissions. The biggest improvement is expected along the Ohio River Valley. Examining the distribution of visibility improvements shows that 15 d yr -1 with lowest sulfate concentrations and least sulfate reduction there will be a just perceptible improvement, while on the other end of the spectrum 15 d yr -1 with the highest sulfate concentration and with the largest sulfate reduction there will be a 35% improvement in extinction. The paper also reviews the assumptions required to carry out the assessment and points out shortcomings in our understanding of the relationship between SO 2 emissions and visibility.

Malm, William C.; Trijonis, John; Sisler, James; Pitchford, Marc; Dennis, Robin L.

168

High Frequency Transitions in the Rotational Spectrum of SO2.  

PubMed

A large number of rotational transitions of 32S16O2, 34S16O2, and 32S18O16O have been measured in the mm-, submm-, and terahertz ( approximately 1 THz) spectral regions. These data sets have been combined with all previously measured SO2 microwave and selected far infrared data to obtain a highly precise set of ground state rotational constants for these isotopomers. The rotational constants for the three isotopomers are in MHz as follows: Parameter32S16O234S16O232S18O16O A60778.54977 (44)58991.18295 (51)59101.1690 (27) B10318.07348 (7)10318.50993 (9)9724.64284 (56) C8799.703399 (70)8761.302481 (97)8331.56018 (51) Centrifugal distortion constants up to P10 are included in the fit. A frequency listing of all the data used in the frequency range between about 7 GHz and 1 THz is included. Copyright 1998 Academic Press. PMID:9724576

Belov; Tretyakov; Kozin; Klisch; Winnewisser; Lafferty; Flaud

1998-09-01

169

40 CFR 97.260 - Submission of CAIR SO2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...false Submission of CAIR SO2 allowance transfers. 97.260 Section 97.260 Protection...TRADING PROGRAMS CAIR SO2 Allowance Transfers § 97.260 Submission of CAIR SO2 allowance transfers. (a) A CAIR authorized...

2013-07-01

170

40 CFR 96.260 - Submission of CAIR SO 2 allowance transfers.  

Code of Federal Regulations, 2013 CFR

...false Submission of CAIR SO 2 allowance transfers. 96.260 Section 96.260 Protection...IMPLEMENTATION PLANS CAIR SO2 Allowance Transfers § 96.260 Submission of CAIR SO 2 allowance transfers. (a) A CAIR authorized...

2013-07-01

171

Global Reactive Gases in the MACC project  

NASA Astrophysics Data System (ADS)

In preparation for the planned atmospheric service component of the European Global Monitoring for Environment and Security (GMES) initiative, the EU FP7 project Monitoring of Atmospheric Composition and Climate (MACC) developed a preoperational data assimilation and modelling system for monitoring and forecasting of reactive gases, greenhouse gases and aerosols. The project is coordinated by the European Centre for Medium-Range Weather Forecast (ECMWF) and the system is built on ECMWF's Integrated Forecasting System (IFS) which has been coupled to the chemistry transport models MOZART-3 and TM5. In order to provide daily forecasts of up to 96 hours for global reactive gases, various satellite retrieval products for ozone (total column and profile data), CO, NO2, CH2O and SO2 are either actively assimilated or passively monitored. The MACC system is routinely evaluated with in-situ data from ground-based stations, ozone sondes and aircraft measurements, and with independent satellite retrievals. Global MACC reactive gases forecasts are used in the planning and analysis of large international field campaigns and to provide dynamical chemical boundary conditions to regional air quality models worldwide. Several case studies of outstanding air pollution events have been performed, and they demonstrate the strengths and weaknesses of chemical data assimilation based on current satellite data products. Besides the regular analyses and forecasts of the tropospheric chemical composition, the MACC system is also used to monitor the evolution of stratospheric ozone. A comprehensive reanalysis simulation from 2003 to 2010 provides new insights into the interannual variability of the atmospheric chemical composition.

Schultz, M. G.

2012-04-01

172

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...

173

Modelling of the long-range transport of volcanic SO2 and ash plumes utilising space-based measurements  

NASA Astrophysics Data System (ADS)

Volcanic eruptions and unrest are among the main natural hazards, which influence nature, human beings and climate. Since volcanic ash and trace gases may damage the material and engines of aircrafts, they also affect air traffic. Most of the active volcanoes are not monitored regularly yet. The combination of satellite observations and atmospheric transport modelling can aid to provide global information on the dispersion and transport of ash and trace gases. One of these trace gases is sulphur dioxide (SO2), which is a good marker for volcanic ash clouds. Within the projects SACS (Support to Aviation Control Service) of GSE-PROMOTE and Exupéry (development of a fast response system for volcanic unrest) SO2 total columns are retrieved from different space-borne instruments (GOME-2, SCIAMACHY and OMI). Relevant parameters such as the location of the emission source, the moment of the eruption as well as the emission height are derived from observations via backward trajectory ensemble matching techniques. Using these parameters the source term for the Lagrangian particle dispersion model FLEXPART is estimated as a first guess. The long-range transport of volcanic SO2 and ash for several days throughout the whole atmosphere as well as for special altitudes is provided. The results have been compared to space-based observations from IASI (Infrared Atmospheric Sounding Interferometer) and AIRS (Atmospheric Infrared Sounder), as well as to ground-based measurements. Furthermore a comparison between the Lagrangian particle dispersion model results and the results of an Eulerian chemical transport model (POLYPHEMUS) using the same source term is shown. Results for recent explosive eruptions will be presented, such as the Etna eruption in May 2008 and the eruptions of the Okmok and Kasatochi volcano in Alaska in July 2008 and August 2008 respectively.

Maerker, C.; Seidenberger, S.; Erbertseder, T.; Valks, P.; Rix, M.; van Geffen, J.

2009-04-01

174

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...

175

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

176

Anomalous Emissions of SO2 During the Recent Eruption of Santa Ana Volcano, El Salvador, Central America  

NASA Astrophysics Data System (ADS)

Santa Ana volcano in western El Salvador, Central America, had a phreatic eruption at 8:05 am (local time) on October 1, 2005, 101 years after its last eruption. However, during the last one hundred years this volcano has presented periods of quiet degassing with fumarolic activity and an acidic lake within its crater. This paper presents results of frequent measurements of SO2 degassing using the MiniDOAS (Differential Optical Absorption Spectroscopy) system and a comparison with the volcanic seismicity prior to the eruption, during, and after the eruption. Vehicle measurements of SO2 flux were taken every hour during the first nine days of the eruption and daily after that. The period of time reported here is from August to December, 2005. Three periods of degassing are distinguished: pre-eruptive, eruptive, and post-eruptive periods. The intense activity at Santa Ana volcano started in July 2005. During the pre-eruptive period up to 4306 and 5154 ton/day of SO2 flux were recorded on October 24 and September 9, 2005, respectively. These values were of the same order of magnitude as the recorded values just after the October 1st eruption (2925 ton/day at 10:01 am). Hourly measurements of SO2 flux taken during the first nine days after the main eruptive event indicate that explosions are preceded by an increase in SO2 flux and that this parameter reaches a peak after the explosion took place. This behavior suggests that increasing accumulation of exsolved magmatic gases occurs within the magmatic chamber before the explosions, increasing the pressure until the point of explosion. A correlation between SO2 fluxes and RSAM (Real Time Seismic Amplitude Measurements) is observed during the complete sampling period. Periodic fluctuations in the SO2 and RSAM values during the entire study period are observed. One possible mechanism explaining these fluctuations it that convective circulation within the magmatic chamber can bring fresh magma periodically to shallow levels, allowing increasing degasification and then decreasing degasification as the batch of magma lowers its gas content, becomes denser, and sinks to give space to a new magma pulse. These results illustrate that the measurements of SO2 flux can provide important warning signals for incoming explosive activity in active volcanoes.

Olmos, Rodolfo; Barrancos, José; Rivera, Claudia; Barahona, Francisco; López, Dina L.; Henriquez, Benancio; Hernández, Agustín; Benitez, Efrain; Hernández, Pedro A.; Pérez, Nemesio M.; Galle, Bo

2007-12-01

177

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

178

SO 2 adsorption and thermal evolution on clean and oxygen precovered Pt(1 1 1)  

NASA Astrophysics Data System (ADS)

We studied the adsorption and reaction of sulfur dioxide on clean and oxygen precovered platinum surfaces by in situ high resolution X-ray photoelectron spectroscopy and discuss earlier, contradicting results. On the clean surface we find flat lying and upright standing SO 2, adsorbing in similar amounts at low temperature. Upon heating, the ratio changes strongly favoring the standing SO 2; subsequently almost all SO 2 desorbs. On the oxygen precovered surface the standing SO 2 is preferably populated and even at low temperatures a direct reaction of SO 2 to SO 3 occurs. Upon heating, SO 2 oxidation to SO 3 and subsequently to SO 4 is found.

Streber, R.; Papp, C.; Lorenz, M. P. A.; Höfert, O.; Darlatt, E.; Bayer, A.; Denecke, R.; Steinrück, H.-P.

2010-07-01

179

Photo-oxidation of SO2 and of SO2 trapped in amorphous water ice studied by IR spectroscopy. Implications for Jupiter's satellite Europa  

NASA Astrophysics Data System (ADS)

Fourier Transform Infrared Spectroscopy (FTIR), is used to characterize thin films of sulfur dioxide trapped in excess of amorphous water ice and to study the photo-oxidation of pure solid SO2 or of SO2 diluted in water ice. These laboratory experiments were undertaken in an attempt to find information on the formation of hydrated sulfuric acid detected on Europa's surface. Vibrational spectra at 30 K of mixed films containing SO2 with an excess of water depend on the deposition conditions. A metastable (SO2)(m)(H2O)(n) phase and a solid solution of SO2 in water ice have been evidenced. Irradiation at 266 nm of mixed films SO2/O-3/H2O produces sulfur trioxide and hydrogen peroxide without traces of sulfuric acid. Irradiation of films of pure SO2, under 200 nm, leads to sulfur trioxide and to ozone. When SO2 is diluted in amorphous water ice, new weak bands that appear after irradiation suggest the formation of sulfuric acid.

Schriver-Mazzuoli, L.; Schriver, A.; Chaabouni, H.

2003-01-01

180

Lagrangian aerosol and ozone precursor forecasts utilizing NASA Aura OMI NO2 and NOAA GOES-GASP AOD Observations  

NASA Astrophysics Data System (ADS)

Over the past decade, the remote sensing of trace gases and aerosols from space has dramatically improved. The emergence and application of these measurements adds a new dimension to air quality management and forecasting by enabling consistent observations of pollutants over large spatial domains. Current instruments aboard NASA and European Space Agency satellites can provide derived measurements of trace gases and aerosols relating directly to most of the EPA's criteria pollutants: ozone, NO2, SO2, CO, and particulate matter (PM10 and PM2.5). Al-Saadi et. al., (2005) provided one of the first demonstrations on the use of AOD as a forecast tool for PM2.5 through IDEA, Infusing satellite Data into Environmental air quality Applications, a joint project between NASA, EPA, and NOAA. We have developed a new approach for forecasting aerosol and ozone precursor levels that utilizes Reverse Domain Filling [Sutton, 1994] techniques and measurements of NO2 from the Ozone Monitoring Instrument (OMI) onboard the NASA Aura satellite and aerosol optical depth (AOD) from NOAA's operational geostationary satellite retrievals [Knapp et al., 2002 and Prados et al. 2007]. Using the LaRC trajectory model [Pierce and Fairlie, 1993], 72-hr back-trajectories are initialized on a uniform grid (0.25° x 0.25°) at the surface over the Midwestern US. Coincidences between the back-trajectories and previous OMI NO2 and GOES AOD observations are identified and used to map the satellite observations back onto the uniform grid at the forecast time. The resulting RDF mapped NO2 forecast is valid at 21Z on the next day. This talk will present a case study for May 2007 over the Western Great Lakes Region. We present a comparison of the RDF forecast to an RDF forecast based on hourly NO2 and SO2 emissions used for CAMx Air Quality Model along with a comparison to in-situ concentrations of PM2.5 and O3. Disclaimer: Although this work was reviewed by the U.S. Environmental Protection Agency, National Oceanic and Atmospheric Administration, and National Aeronautics and Space Administration, and approved for publication, it may not necessarily reflect official Agency policy.

Pierce, R. B.; Szykman, J.; Kondragunta, S.; Al-Saadi, J.; Hertherington, G.; Majewski, M.; Kittaka, C.

2008-05-01

181

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

EPA Science Inventory

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

182

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

183

SO 2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat  

Microsoft Academic Search

To improve interpretation of volcanic SO2 flux data, it is necessary to quantify and understand reactions involving SO2 in volcanic plumes. SO2 is lost in volcanic plumes through a number of mechanisms. Here we report SO2 measurements made with miniature ultraviolet spectrometers at Soufrière Hills volcano, Montserrat; a low altitude volcano (~1000 m above sea level) whose plume entrains humid marine

Lizzette A. Rodríguez; I. Matthew Watson; Marie Edmonds; Graham Ryan; Vicky Hards; Clive M. M. Oppenheimer; Gregg J. S. Bluth

2008-01-01

184

The Rotational Spectrum of SO2 and the Determination of the Hyperfine Constants and Nuclear Magnetic Shielding Tensors of (33)SO2 and SO(17)O  

NASA Astrophysics Data System (ADS)

Precise frequencies for the 111 - 202 transition of (33)SO2 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)SO2 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 O3 molecule. The transition mentioned above was also measured for (32)SO2, (34)SO2, SO(18)O, and vibrationally excited (v2 = 1) (32)SO2. For (33)SO2, some transitions with large hyperfine splitting were also recorded in the millimeter wave region. Continuing our investigations of the rotational spectra of SO2 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 Ka up to 63 and 16, respectively. Transitions with high Ka, up to 28, have been recorded with the JPL Laser Sideband Spectrometer between 1.8 and 3.2 THz.

Müller, Holger S. P.; Farhoomand, Jam; Cohen, Edward A.; Brupbacher-Gatehouse, Bethany; Schäfer, Martin; Bauder, Alfred; Winnewisser, Gisbert

2000-05-01

185

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

Code of Federal Regulations, 2013 CFR

...data procedures for SO2, NOX, and flow rate. 75.33 Section 75.33 ...procedures for SO2 , NOX , and flow rate. (a) Following initial certification...the required SO2 , NOX , and flow rate monitoring system(s) at a...

2013-07-01

186

Removal of Magnesia from Dolomitic Southern Florida Phosphate Concentrates by Aqueous SO2 Leaching.  

National Technical Information Service (NTIS)

The Bureau of Mines has investigated the SO2 leaching of MgO from high-MgO-bearing Florida phosphate concentrates. The SO2 was effective in leaching some of the MgO from three phosphate concentrates; flow rate of the SO2 and leach time were major factors ...

J. P. Hansen B. E. Davis T. O. Llewellyn

1985-01-01

187

The effects of SO2 on Dobson and Brewer total ozone measurements  

NASA Astrophysics Data System (ADS)

Sulphur dioxide has strong absorption bands in the ultraviolet at wavelengths which are used to measure atmospheric ozone. Total ozone measurements are, therefore, affected by the presence of atmospheric SO2. Measurements made at Toronto using the Dobson and Brewer ozone spectrophotometers have indicated interference by SO2. Two methods of identifying and correcting for SO2 interference in the Dobson measurements are suggested.

Evans, W. F. J.; Asbridge, I. A.; Kerr, J. B.; Mateer, C. L.; Olafson, R. A.

188

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

189

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 ...

190

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2013 CFR

... (i) When conducting the daily calibration error tests of the SO2 monitoring...appendix B of this part, the zero-level calibration gas shall have an SO2 concentration...startup. (ii) EPA recommends that the calibration response of the SO2 monitoring...

2013-07-01

191

Hot exhaust gases with passive FTIR emission spectroscopy  

NASA Astrophysics Data System (ADS)

Passive FTIR emission spectroscopy using a commercial medium resolution instrument with a telescope has been applied to analyze the hot exhaust gases of various combustion sources, such as industrial and building smoke stacks, aircraft engines, flares, and forest fires. To interpret the remotely measured spectra a multi-layer, line-by-line spectra retrieval software using the molecular spectral databases HITRAN and HITEMP has been developed, validated and successfully used to determine the exhaust gas temperatures and the concentrations of CO2, H2O, CO, N2O, CH4, NO, NO2, SO2, and HCl for different combustion conditions of the sources. In this paper the feasibility and the setup of passive IR measurements, the basic theory of radiative transfer and special features of the commercially available spectra analysis code are described. In addition, the results of the different measurement applications are summarized.

Heland, Joerg; Schaefer, Klaus; Haus, Rainer

1998-12-01

192

Trends in stratospheric NO2  

NASA Astrophysics Data System (ADS)

Data of spectrometric ground-based measurements of stratospheric column NO2 contents at stations within the Network for the Detection of Atmospheric Composition Change (NDACC) are analyzed for linear trends. The trend analysis takes into account the NO2 seasonal variation, effects of the 11-year solar and geomagnetic activity cycles, effects of the quasi-biennial oscillation and the El Nino - Southern Oscillation, and the effects of the El Chichon and Pinatubo eruptions. The latitudinal distributions of the annual and seasonal trends in NO2 have been obtained. The annual trends are mostly positive in the southern hemisphere middle and low latitudes and negative in the European sector of the northern hemisphere middle latitudes. In the high and polar latitudes of the two hemispheres, the annual estimates of trends are mostly statistically insignificant. However, a positive NO2 trend is observed at 78°S in the Antarctic, while positive and negative trends are observed in the northern hemisphere high latitudes. The maximum positive and negative trends are about 10% per decade by module. Seasonal estimates of the trends differ generally from the annual estimates. At stations of Zvenigorod, Jungfraujoch (northern hemisphere middle latitudes), Lauder, and Macquarie Island (southern hemisphere middle latitudes) the signs of the NO2 trends do not depend on season, although the trend values vary with season. At other stations, trend values, their statistical significance, and even their signs can vary with season. Nitrogen oxides affects the photochemical balance of stratospheric ozone directly and indirectly, influencing the effectiveness of ozone destruction in the chlorine cycle. The observed significant trends in stratospheric NO2 should result in noticeable perturbations of the rates of ozone destruction in the nitrogen cycle. The sensitivities of photochemical balance of stratospheric ozone to long-term changes in stratospheric NO2 and chlorine are estimated using a combination of analytical and one-dimensional photochemical models.

Gruzdev, A. N.

2009-04-01

193

Greenhouse Gases  

MedlinePLUS

... support life as we know it. Without the greenhouse effect, the average temperature of the Earth would be ... regulated independently of its warming effects. More about greenhouse gases’ effect on the climate » Also on Energy Explained Energy ...

194

SO2 inhalation causes synaptic injury in rat hippocampus via its derivatives in vivo.  

PubMed

SO2 remains a common air pollutant, almost half of the world's population uses coal and biomass fuels for domestic energy. Limited evidence suggests that exposure to SO2 may be associated with neurotoxicity and increased risk of hospitalization and mortality of many brain disorders. However, our understanding of the mechanisms by which SO2 causes harmful insults on neurons remains elusive. To explore the molecular mechanism of SO2-induced neurotoxic effects in hippocampal neurons, we evaluated the synaptic plasticity in rat hippocampus after exposure to SO2 at various concentrations (3.5 and 7mgm(-3), 6hd(-1), for 90d) in vivo, and in primary cultured hippocampal neurons (DIV7 and DIV14) after the treatment of SO2 derivatives in vitro. The results showed that SYP, PSD-95, NR-2B, p-ERK1/2 and p-CREB were consistently inhibited by SO2/SO2 derivatives in more mature hippocampal neurons in vivo and in vitro, while the effects were opposite in young hippocampal neurons. Our results indicated that in young neurons, SO2 exposure produced neuronal insult is similar to ischemic injury; while in more mature neurons, SO2 exposure induced synaptic dysfunctions might participate in cognitive impairment. The results implied that SO2 inhalation could cause different neuronal injury during brain development, and suggested that the molecular mechanisms might be involved in the changes of synaptic plasticity. PMID:24099899

Yun, Yang; Yao, Gaoyi; Yue, Huifeng; Guo, Lin; Qin, Guohua; Li, Guangke; Sang, Nan

2013-10-04

195

Dominating influence of nh 3 on the oxidation of aqueous SO 2: The coupling of NH 3 and SO 2 in atmospheric water  

NASA Astrophysics Data System (ADS)

The oxidation of SO 2 in atmospheric water (cloud, rain, liquid aerosol and fog) is influenced by the presence of NH 3. The enhancing effect of NH 3 is especially pronounced if the oxidation occurs with an oxidant such as O 3 for which the reaction rate increases strongly with increasing pH, because NH 3 (i) codetermines the pH of the water and thus in turn the solubility of SO 2, and (ii) provides acid neutralizing capacity as well as buffer intensity to the heterogeneous atmosphere-water system in counteracting the acidity produced by the oxidation of SO 2. At low buffer intensity, the acidity production leads to the alleviation of further SO 2-oxidation. A computer model is used to assess the influence of SO 2, NH 3 and other potential acids and bases, of aerosols and of the liquid water content on the composition and its temporal variation of closed or open atmospheric systems as a consequence of SO 2 oxidation by O 3. An essential corollary to this model is a definition of atmospheric alkalinity (or acidity). Model results are compared with field data obtained in measuring the temporal variation in urban/rural fog composition.

Behra, Philippe; Sigg, Laura; Werner, Stumm

196

Chemical interactions between mineral dust particles and acid gases during Asian dust events  

NASA Astrophysics Data System (ADS)

Acid gas reactions during the passage from the source regions to the western North Pacific modify the chemical characteristics of Asian mineral dust particles as they pass through heavily industrial regions. We conducted aerosol samplings to investigate the interaction of mineral dust particles with acid gases in the western North Pacific region during the high-dust season. The concentration peaks of NO3- and mineral dust particles were in the coarse mode range (D > 1.25 ?m) in all aerosol samples, while non-sea-salt-(nss)-SO42- had an apparent peak in the coarse mode range only in an Asian dust event that experienced rain. Nitrate was the dominant acid substance associated with the mineral dust particles rather than nss-SO42-. In the urban air of Tokyo we also conducted an in situ experiment to react ambient acid gases with mineral dust particle loaded on a filter. The in situ experiment indicated that HNO3 had reacted with mineral dust particles much more efficiently than SO2 had. HNO3 (+NO2) and HCl accounted for large fractions (48% and 40%) of acid gases that reacted with mineral dust particles, while SO2 accounted for a small fraction (12%). The high adsorption of HNO3 on mineral dust particles would change their surface properties from hydrophobic to hygroscopic and form an efficient mechanism to remove nitrogen compounds to the ocean surface layer.

Ooki, Atsushi; Uematsu, Mitsuo

2005-02-01

197

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...

198

The use of passive sampling to monitor forest exposure to O 3, NO 2 and SO 2: a review and some case studies  

Microsoft Academic Search

The use of passive sampler systems is reviewed and discussed. These devices are able to determine both spatial and temporal differences in canopy exposure, as is demonstrated by their use in extensive monitoring of air-pollution exposure in forest health plots. Categorising forest health monitoring plots according to air-pollution exposure permits cause–effect analysis of certain forest health responses. In addition, passive

Roger M Cox

2003-01-01

199

Dissolution potential of SO2 Co-injected with CO2 in geologic sequestration.  

PubMed

Sulfur dioxide is a possible co-injectant with carbon dioxide in the context of geologic sequestration. Because of the potential of SO2 to acidify formation brines, the extent of SO2 dissolution from the CO2 phase will determine the viability of co-injection. Pressure-, temperature-, and salinity-adjusted values of the SO2 Henry's Law constant and fugacity coefficient were determined. They are predicted to decrease with depth, such that the solubility of SO2 is a factor of 0.04 smaller than would be predicted without these adjustments. To explore the potential effects of transport limitations, a nonsteady-state model of SO2 diffusion through a stationary cone-shaped plume of supercritical CO2 was developed. This model represents an end-member scenario of diffusion-controlled dissolution of SO2, to contrast with models of complete phase equilibrium. Simulations for conditions corresponding to storage depths of 0.8-2.4 km revealed that after 1000 years, 65-75% of the SO2 remains in the CO2 phase. This slow release of SO2 would largely mitigate its impact on brine pH. Furthermore, small amounts of SO2 are predicted to have a negligible effect on the critical point of CO2 but will increase phase density by as much as 12% for mixtures containing 5% SO2. PMID:20000315

Crandell, Lauren E; Ellis, Brian R; Peters, Catherine A

2010-01-01

200

Force field of the TMGL ionic liquid and the solubility of SO2 and CO2 in the TMGL from molecular dynamics simulation.  

PubMed

An all-atom force field is developed using a combination of density functional theory calculations and OPLS force field parameter values for the 1,1,3,3-tetramethylguanidium lactate (TMG) lactic acid (LAC) ionic liquid (TMGL). The computed density of the TMGL is in good agreement with available experimental values. The internal energy components, cohesive energy density, and the self-diffusion constants are also discussed. Molecular dynamics simulations are then conducted to investigate the solubility of the SO2 and CO2 gases in the TMGL. The simulation results show strong organization of SO2 about the TMG cation and the LAC anion, especially the LAC anion, but relatively weak organization of CO2 about the cation and the anion of the TMGL, which explained well the selectivity of the TMGL toward the SO2 and CO2. PMID:17691721

Wang, Yong; Pan, Haihua; Li, Haoran; Wang, Congmin

2007-08-10

201

Detection of SO2, HCl and CO2 in Arenal Volcano Eruptive Plume Using MASTER Multispectral Images  

NASA Astrophysics Data System (ADS)

The Costa Rica Airborne Research and Technology Applications (CARTA) Mission developed in March-April, 2003 was a join effort between the National Program for Airtransported Missions of the National Center for High Technology of Costa Rica formed by the four public universities in Costa Rica, and NASA. This mission took aerial infrared photography and multiespectral images using the MASTER sensor of 70% of the national territory of Costa Rica. Multiespectral images were taken from Arenal volcano at high (13780 m) and at low (3450 m) altitude. The MASTER images have an aperture ranging between 0.44 micrometers in the visible and 13 micrometers in the thermic infrared. In addition, the distribution of the 50 channels of the MASTER sensor, have been arranged to avoid the influence of water vapor, always present in large quantities in the atmosphere and also in volcanic gases. We determined that SO2 is clearly visible between 8.5-9.3 micrometers (LWIR), and CO2, H2S and HCl in a smaller bandwidth 3.5-4.4 micrometers (MWIR). Another gas detected at Arenal volcanic plumes is methane, in a bandwidth between 7.7-8.1 micrometers (LWIR). When both multispectral images were taken, Arenal volcano had an active lava flow descending its NE flank and no significative winds were blowing, so the eruptive plume was rising almost vertically from the active vent. Profiles of gas concentration collected from the above mentioned bands were performed on the image using the software ENVI to detect different species present in volcanic gases. The concentration of volcanic gases in the multiespectral image was largest above the active crater (north vent of Crater C), and lower on the short active lava flow whose blocks were cascading down up to 1 km on the NE flank. Significant amounts of SO2 were measured above the lava flow and the fan of cascading blocks suggesting that the cooling lava continues to release magmatic gases as their cascading blocks move down flank of the volcano. The higher resolution of the low altitude multispectral image assured better results when measuring volcanic gas species.

Bonatti, J.; Berrocal, M.; Malavassi, E.

2004-12-01

202

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

203

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

204

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

Microsoft Academic Search

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

S. Bekki

1995-01-01

205

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

Microsoft Academic Search

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

S. Bekki

1995-01-01

206

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

Microsoft Academic Search

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

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

2006-01-01

207

Volcanic SO2 Emissions vs. Seismicity - July 2002 LP Swarm, Soufriere Hills Volcano, Montserrat  

Microsoft Academic Search

Volcanic sulfur dioxide (SO2) measurements of passive plumes have recently improved with the application of Differential Optical Absorption Spectroscopy (DOAS). In January 2002, the Montserrat Volcano Observatory installed two fixed DOAS instruments which collect rapid, continuous measurements of SO2 emissions. For the first time, SO2 fluxes are being collected on a time scale of minutes, allowing short-term changes to be

J. Shannon; G. Bluth; M. Edmonds; G. Thompson

2003-01-01

208

New discoveries enabled by OMI SO2 measurements and future missions  

Microsoft Academic Search

The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. This talk highlights most recent science results enabled by using OMI SO2 data. OMI daily contiguous volcanic SO2 data continue 25+ climatic record by its predecessors (Total

Nickolay Krotkov

2010-01-01

209

Prediction of SO 2 removal efficiency for wet Flue Gas Desulfurization  

Microsoft Academic Search

The wet Flue Gas Desulfurization in the coal-fired power plants has been the most widely used because of its high SO2 removal efficiency, reliable and low utility consumption. The difficulty in the prediction of the SO2 removal from flue gas is that the performance of the system is related to a wide range of variables. In this paper, the SO2

Binlin Dou; Weiguo Pan; Qiang Jin; Wenhuan Wang; Yu Li

2009-01-01

210

Comparison of COSPEC and two miniature ultraviolet spectrometer systems for SO 2 measurements using scattered sunlight  

Microsoft Academic Search

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\\u000a a COSPEC by measuring SO2 column amounts at K?lauea Volcano, Hawaii. The two systems, one calibrated using in-situ SO2 cells, and the other using a calibrated laboratory reference spectrum,

Tamar Elias; A. Jeff Sutton; Clive Oppenheimer; Keith A. Horton; Harold Garbeil; Vitchko Tsanev; Andrew J. S. McGonigle; Glyn Williams-Jones

2006-01-01

211

China's 11th Five-Year Plan and the Environment: Reducing SO2 Emissions  

Microsoft Academic Search

China's rapid economic growth has been accompanied by a high level of environmental degradation. One of the major sources of health and ecosystem damages is sulfur dioxide (SO2). Reducing SO2 emissions is a priority of China's environmental authorities, and the 11th Five-Year Plan (2006–2010) includes the target of reducing total SO2 emissions by 10 percent from the 2005 level. Given

Jing Cao; Richard Garbaccio; Mun S. Ho

2009-01-01

212

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

Microsoft Academic Search

Recently, SO2 and NOx have become serious air pollutants in the form of photochemical smog and acid rain. In spite of attempts to reduce the amount of SO2 and NOx emitted, the density of SO2 and NOx in the atmosphere has remained on a stable level, or even become worse. Here, we designed a novel type of needle-water electrode corona

Limin Dong; Shouguo Sheng; Lutao Liu; Jiaxiang Yang; Xiaochun Chi

2002-01-01

213

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

Microsoft Academic Search

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

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

2001-01-01

214

The NOAA Near Real-time OMI-SO2 Cloud Visualization and Product Distribution System  

Microsoft Academic Search

The Ozone Monitoring Instrument (OMI) on the NASA EOS\\/Aura research satellite allows measurement of SO2 concentrations at UV wavelengths with daily global coverage. SO2 is detected from space using its strong absorption band structure in the near UV (300-320 nm) as well as in IR bands near 7.3 and 8.6 mm. Thirty years of UV SO2 measurements with the Total

G. Vicente; G. Serafino; A. Krueger; S. Carn; K. Yang; N. Krotkov; M. Guffanti; P. Levelt

2007-01-01

215

SO2 oxidation over the V2O5\\/TiO2 SCR catalyst  

Microsoft Academic Search

The effects of V2O5 loading of the V2O5\\/TiO2 SCR catalyst on SO2 oxidation activity were examined by infrared spectroscopy (DRIFT) and SO2 oxidation measurement. Vanadium oxide added to the catalyst was found to be well dispersed over the TiO2 carrier until covered with monolayer V2O5. The rate of SO2 oxidation increased almost linearly with V2O5 loading below the monolayer capacity

Hiroyuki Kamata; Hiroaki Ohara; Katsumi Takahashi; Akinori Yukimura; Yorimasa Seo

2001-01-01

216

SO 2 reaction with Ca(OH) 2 at medium temperatures (300–425°C)  

Microsoft Academic Search

The study of the reaction between Ca(OH)2 and SO2 has been performed in the medium temperature range (300–450°C) under controlled dehydration conditions. The largest SO2 capture has been found at 450°C, 0.64 mol SO2 mol Ca-1, and no influence of the water vapour pressure on the sorbent utilization has been observed. The investigation of the internal porous structure of Ca(OH)2

Ignacio Fernández; Aurora Garea; Angel Irabien

1998-01-01

217

Temporal-spatial variations of tropospheric SO2 over China using SCIAMACHY satellite observations  

Microsoft Academic Search

The data products of monthly average troposphric SO2 vertical column densities over China from January 2004 to November 2009 are acquired from the SCIAMACHY instrument on board ENVISAT. The results of monthly average tropospheric SO2 vertical column densities were analyzed to research the temporal-spatial distribution and change trends of tropospheric SO2 over China. In this paper, we selected four typical

Xiaohua Xu; Hong Jiang; Yueqi Wang; Xiuying Zhang

2010-01-01

218

OMI measurements of SO2 pollution over Eastern China in 2005-2008  

Microsoft Academic Search

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. OMI seasonal to multi-year average images clearly show the world-highest consistent SO2 pollution in northeast China. China is the world's largest SO2 emitter, mostly due to the

N. Krotkov; K. Pickering; J. Witte; S. Carn; K. Yang; G. Carmichael; D. Streets; Q. Zhang; C. Wei

2009-01-01

219

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

220

OMI measurements of SO2 pollution over Eastern China in 2005-2008  

NASA Astrophysics Data System (ADS)

The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. OMI seasonal to multi-year average images clearly show the world-highest consistent SO2 pollution in northeast China. China is the world's largest SO2 emitter, mostly due to the burning of high-sulfur coal in its many coal-fired power plants, which lack the technology used in many other countries to remove sulfur from smoke stack emissions. China's government has instituted nationwide measures to control SO2 emissions through the adoption of flue-gas desulfurization technology on new power plants; and even greater measures were adopted in the Beijing area in anticipation of the Olympic Games. To study the environmental effects of the emission controls we compared OMI SO2 time series over eastern China for 2005 through 2008. The time series have been done as 7-day running means of the cloud-free daily observations. By mid-March we started to see substantial periods of lower SO2 values in 2008 compared to 2007, and by mid June the 2008 values were consistently lower than 2007 and prior years. The decline is widespread with highest SO2 typically located to the south and southwest of Beijing in regions with large clusters of power plants and also around Shanghai. The decline also lasted beyond the Olympic season. We do not yet know to what extent the economic downturn in China (and reduced industrial production) contributed to lower SO2 levels in the fall of 2008. We have also compared the observed and modeled fields using University of Iowa STEM model for the period June - September 2008. The model provided SO2 vertical distributions as well as aerosol vertical profiles that were used to correct OMI operational SO2 retrievals and improve the comparisons. The OMI SO2 changes in 2008 have also been compared with the estimated changes in SO2 emissions derived from a bottom-up analysis of the SO2 reduction measures put into place for the Olympics. Finally we present our plans to use the OMI SO2 columns to provide a top-down constraint on SO2 regional emissions.

Krotkov, N.; Pickering, K.; Witte, J.; Carn, S.; Yang, K.; Carmichael, G.; Streets, D.; Zhang, Q.; Wei, C.

2009-05-01

221

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

222

Detection of SO2 on Callisto with the Hubble Space Telescope  

Microsoft Academic Search

We have detected SO2 in ultraviolet spectra of Callisto obtained with the Hubble Space Telescope's Faint Object Spectrograph. An absorption band centered at 280 nm appears in the spectrum of Callisto's leading hemisphere, but is not apparent in the spectrum of the trailing hemisphere. The band is similar to the SO2 band on Europa's trailing hemisphere. Callisto's leading hemisphere spectrum

Keith S. Noll; Robert E. Johnson; Melissa A. McGrath; John J. Caldwell

1997-01-01

223

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,...

224

40 CFR 74.23 - 1985 Allowable SO2 emissions rate.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false 1985 Allowable SO2 emissions rate. 74.23...Calculations for Combustion Sources § 74.23 1985 Allowable SO2 emissions rate. (a...commenced operation prior to January 1, 1985, the calendar year for the allowable...

2010-07-01

225

40 CFR 74.23 - 1985 Allowable SO2 emissions rate.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false 1985 Allowable SO2 emissions rate. 74.23...Calculations for Combustion Sources § 74.23 1985 Allowable SO2 emissions rate. (a...commenced operation prior to January 1, 1985, the calendar year for the allowable...

2009-07-01

226

Synthesis of [N(CH3)4]2O3SOSO2(s) and [N(CH3)4]2[(O2SO)2SO2SO2(s) containing (SO4)(SO2)x(2-) x = 1, 2, members of a new class of sulfur oxydianions.  

PubMed

One mole equivalent of SO2 reversibly reacts with [N(CH3)4]2SO4(s) to give [N(CH3)4]2S2O6(s) (1) containing the [O3SOSO2](2-), shown by Raman and IR to be an isomer of the [O3SSO3](2-) dianion. The experimental and calculated (B3PW91/6-311+G(3df)) vibrational spectra are in excellent agreement, and the IR spectrum is similar to that of the isoelectronic O3ClOClO2. Crystals of [N(CH3)4]2(O2SO)2SO2·SO2 (2) were isolated from solutions of [N(CH3)4]2SO4 in liquid SO2. The X-ray structure showed that 2 contained the [(O2SO)2SO2](2-) dianion. The characterized N(CH3)4(+) salts 1 and 2 are the first two members of the (SO4)(SO2)x(2-) class of sulfur oxydianions analogous to the well-known small cation salts of the SO4(SO3)x(2-) polysulfates. PMID:23734691

Bruna, Pablo; Decken, Andreas; Grein, Friedrich; Passmore, Jack; Rautiainen, J Mikko; Richardson, Stephanie; Whidden, Tom

2013-06-04

227

Interspecfic Variation in SO2 Flux - Leaf Surface 'Versus' Internal Flux, and Components of Leaf Conductance.  

National Technical Information Service (NTIS)

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: Pis...

D. M. Olszyk D. T. Tingey

1985-01-01

228

The origin of sulfur MIF effects in ancient rocks based on isotopic SO2 cross sections  

NASA Astrophysics Data System (ADS)

The discovery of unusual sulfur isotope fractionation in Archean and Paleoproterozoic (> 2.4 Ga) rocks has promised to yield insights into the rise of O2 and the nature of the sulfur cycle on ancient Earth, but interpretation has been hampered by the lack of a clear mechanism for the sulfur isotope signature. Proposed mechanisms for the unusual sulfur isotope signatures (termed mass-independent fractionation or MIF) include SO2 photolysis, atmospheric S3 (thiozone) formation, and thermal sulfate reduction in sediments. We report high-resolution ultraviolet cross section measurements of the sulfur isotopologues of SO2 that demonstrate that SO2 photolysis yields a sulfur MIF signature due to small offsets in the cross sections for low abundances of SO2 (~0.1 ppb), with additional MIF by self-shielding by 32SO2 at higher abundances (up to ~3 ppb). The required atmospheric abundances of SO2 are consistent with variable SO2 injection rates from volcanic plumes, with rates comparable to modern day to about 10 times modern. A recent suggestion that OCS was an abundant greenhouse gas in the Archean, based on low-resolution SO2 cross section data, is not supported by our results.

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

2012-04-01

229

LONG-RANGE TRANSPORT AND TRANSFORMATION OF SO2 AND SULFATE  

EPA Science Inventory

Technical descriptions and computer programs are presented for two models that calculate long-range transport, diffusion, transformation of SO2 to sulfate, and dry and precipitation deposition of initially emitted SO2. One model treats the mixing layer height as constant; the oth...

230

HYBRID RECEPTOR MODEL FOR SECONDARY SULFATE FROM AN SO2 POINT SOURCE  

EPA Science Inventory

A formalism is presented for calculating the ambient concentration of secondary sulfate at any downwind distance from an SO2-emitting point source. The SO2 is assumed to be affected by dispersion, dry deposition and homogeneous gas phase oxidation processes having arbitrary time ...

231

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

Microsoft Academic Search

Significant variations are apparent between the various reported regional and global ship SO2 emission inventories. Important parameters for SO2 emission modelling are sulphur contents and marine fuel consumption. Since 1993, the global average sulphur content for heavy fuel has shown an overall downward trend, while the bunker sale has increased. We present an improved bottom up approach to estimate marine

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

2005-01-01

232

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...

233

Experimental SO2 Removal System and Waste Disposal Pond, Widows Creek Steam Plant, Alabama.  

National Technical Information Service (NTIS)

TVA proposes to install a full-scale research and demonstration wet-limestone SO2 scrubber on unit 8 of the Widows Creek Steam Plant, Jackson County, Alabama, in order to develop technology for removing sulfur dioxide (SO2), and to construct a new disposa...

1973-01-01

234

Role of Porosity Loss in Limiting SO2 Capture by Calcium Based Sorbents.  

National Technical Information Service (NTIS)

The article discusses a study to determine the role of porosity loss in limiting SO2 capture by calcium based sorbents. The extent of high temperature (900-1300 C), short time (<1 s) SO2 capture was found to be limited by temperature dependent losses in t...

G. H. Newton S. L. Chen J. C. Kramlich

1989-01-01

235

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

NASA Astrophysics Data System (ADS)

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 multiplying by the plume's transport speed. However, plume velocities are usually derived from ground-based anemometers, located many kilometers from the traverse route and hundreds of meters below plume altitude, complicating the experimental design and introducing large flux (can be >100%) errors. Here we present the first report of a single instrument capable of (accurate) volcanic SO2 flux measurements. This device records integrated SO2 concentrations and plume heights during traverses. Between traverses, two in-plume SO2 time series are measured from underneath the plume with the instrument, corresponding to zenith and inclined (user-specified angle from vertical in the direction of the volcano) fields of view, respectively. The distance between the points of intersection of the two views with the plume is found on the basis of the determined plume height, and the two signals are cross-correlated to determine the lag between them, enabling accurate derivation of the wind speed. We present flux data (with errors ?±12%) obtained in this way at Mt. Etna during July 2004.

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

2005-02-01

236

Estimativa da Taxa de Precipitacao de SO2 Antropogenico na Grande Sao Paulo (Estimation of the Precipitation Rate of Anthropogenic SO2 in the Greater Sao Paulo Region).  

National Technical Information Service (NTIS)

Using the CETESB data of the SO2 concentration and emission rate over Great Sao Paulo, an annual deposition rate of the pollutant, for this region and its surroundings, was estimated. A pollutant deposition numerical model was used for obtaining these est...

C. Monteirodoespiritosanto L. M. Moreiranordemann

1987-01-01

237

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

238

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

NASA Astrophysics Data System (ADS)

The oxidation of volcanic SO2 to sulfate in the stratosphere is investigated for an anomalously large volcanic sulfur loading (approximately 200 Mt) similar to that generated by the Tambora eruption in 1815. Model calculations suggest that stratospheric OH levels can be severely reduced by the gas-phase oxidation of SO2. One implication of this is that dense volcanic SO2 clouds may last substantially longer than previously thought. SO2 oxidation is also found to lead to significant stratospheric dehydration because approximately three molecules of H2O are consumed for each molecule of SO2 converted to sulfate. Therefore it is possible to view major volcanic eruptions as a potential sink for stratospheric H2O.

Bekki, S.

1995-04-01

239

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

240

Reconstruction of SO 2 flux emission chronology from space-based measurements  

NASA Astrophysics Data System (ADS)

Infrared satellite images measured with the MODIS instrument of the volcanic plume produced during the 2006 eruption of Mt. Etna were analysed to produce maps of SO 2 amount. We used these maps to reconstruct time series of SO 2 fluxes by integrating profiles of SO 2 orthogonal to the plume advection direction and multiplying with wind speeds from a meteorological model. These data were then compared with a reconstructed time series of SO 2 fluxes measured with the FLAME ground-based network of ultraviolet DOAS systems surrounding the volcano. We found weak agreement on 3rd December when little ash was emitted, but this agreement improved when a 0.3 m s - 1 wind speed correction factor was used. FLAME and MODIS results were in good agreement on the 6th December, and improved when a - 0.3 m s - 1 offset was applied. The corrected data revealed that the only period of time when FLAME and MODIS did not track together was coincident with the presence of ash, which interferes with the IR imagery and retrieval of SO 2 . We highlight that combining two independent time series of SO 2 flux allows a precise determination of wind speed, if there is sufficient time-dependent structure in the SO 2 signal. The observed increase in SO 2 flux prior to the ash emission is interpreted as a quiescent release of an accumulated gas phase that drive eruptive activity, as previously suggested for the southeast crater system of Etna. In this case the SO 2 flux signal therefore acted as a precursor to the eruptive ash events. This work demonstrates that quantitative reconstruction of SO 2 flux time series is feasible using MODIS data, opening a new frontier in the use of satellite data to interpret volcanic processes, in particular in poorly monitored remote locations.

Merucci, Luca; Burton, Michael; Corradini, Stefano; Salerno, Giuseppe Giovanni

2011-09-01

241

Toxic gases.  

PubMed Central

An overview of the widespread use of gases and some volatile solvents in modern society is given. The usual circumstances in which undue exposure may occur are described. The most prominent symptoms and general principles of diagnosis and treatment are given and are followed by more specific information on the commoner, more toxic materials. While acute poisonings constitute the greater part of the paper, some indication of chronic disorders arising from repeated or prolonged exposure is also given.

Matthews, G.

1989-01-01

242

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

243

Electric field induced silicon carbide nanotubes: a promising gas sensor for detecting SO2  

NASA Astrophysics Data System (ADS)

Finding an effective strategy for detecting SO2 gas is very important in order to solve the problem of pollution of SO2. Based on the first-principles density functional theory (DFT) calculations, we herein explore the possibility of using (5, 5) silicon carbide nanotubes (SiCNTs) with an external electric field (EF) as a potential gas sensor for SO2 detection. It is found that SO2 molecules can be chemisorbed to the Si-C bonds of SiCNTs and can generate a different charge distribution under the EF, resulting in the breaking of some S-C bonds. It is these broken S-C bonds that induce a decrease in the band gap. Furthermore, with the concentration of SO2 exceeding 20%, the band gap of SiCNT under an EF of 9.00 V nm-1 would be reduced from 1.75 eV for SiCNT to zero, indicating the transformation from a semiconductor to a conductor. Hence, with an appropriate EF, SiCNTs can effectively respond to SO2 and serve as sensors for detecting SO2 gas.

Jia, Y. B.; Zhuang, G. L.; Wang, J. G.

2012-02-01

244

Measurements of dimethyl sulfide and SO2 during GTE/CITE 3  

SciTech Connect

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

Ferek, R.J.; Hegg, D.A. [Univ. of Washington, Seattle, WA (United States)

1993-12-01

245

SO2 inhalation contributes to the development and progression of ischemic stroke in the brain.  

PubMed

Epidemiological literatures show an association between air pollution and ischemic stroke, and effective pollutants may include SO(2), NO(x), O(3), CO, and particulates. However, existing experimental studies lack evidence as to the presence of effects for SO(2), which has been the focus in developing countries with increasing use of coal as the main resource. In the present study, we treated Wistar rats with SO(2) at various concentrations and determined endothelin-1 (ET-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and intercellular adhesion molecule 1 (ICAM-1) messenger RNA (mRNA) and protein expression in the cortex. The results show that SO(2) elevated the levels of ET-1, iNOS, COX-2, and ICAM-1 mRNA and protein in a concentration-dependent manner. Then, we set up rat model of ischemic stroke using middle cerebral artery occlusion (MCAO) and further treated the model rats with filtered air and lower concentration SO(2) for the same period. As expected, elevated expression of ET-1, iNOS, COX-2, and ICAM-1 occurred in the cortex of MCAO model rats exposed to filtered air, followed by increased activation of caspase-3 and cerebral infarct volume. Interestingly, SO(2) inhalation after MCAO significantly amplified above effects. It implies that SO(2) inhalation caused brain injuries similar to that of cerebral ischemia, and its exposure in atmospheric environment contributed to the development and progression of ischemic stroke. PMID:20083630

Sang, Nan; Yun, Yang; Li, Hongyan; Hou, Li; Han, Ming; Li, Guangke

2010-01-18

246

Molecular transport and phase transition of polycrystalline ice doped with HCl and SO2 near its melting point  

NASA Astrophysics Data System (ADS)

HCl and SO2 are major trace gases in atmosphere, which greatly affects chemical properties of atmospheric ice particles. A particular interest to atmospheric science is the effects of impurities on molecular transport and phase transition at grain boundaries in polycrystalline ice. Effects of doped HCl and SO2 on transport and phase transition at grain boundary of 2-4 micrometer polycrystalline ice were studied using a novel technique - Fast Thermal Desorption Spectroscopy (FTDS) [1] in the temperature range from -2 to -20 deg. C. In these experiments, H2O/D2O/H2O sandwich-like polycrystalline ice films doped with HCl and SO2 were vapor- deposited on the surface of a thin filament positioned in a vacuum chamber and maintained initially at cryogenic temperatures. After the deposition, the temperature of the filament was rapidly raised to a value near ice melting point, thus, initiating rapids H/D exchange reaction at the interface of H2O and D2O layers. Diffusion controlled rate of isotopic exchange in the desorbing film was monitored with a sensitive mass-spectrometer making it possible to gain quantitative information of the extent of diffusion of chemical species along the grain boundaries in polycrystalline ice samples. Comparisons of the experimental results in pure and doped polycrystalline ice show that water self diffusivity at the grain boundaries is significantly enhanced (by at least an order of magnitude) in the presence of HCl or SO2. The strong, non- Arrhenius, dependence of the water self-diffusivity on temperature indicates that this is due to grain boundary premelting [2], which may occur at temperatures as low as 10 deg. below ice melting point. We will discuss implication of this and other results of our FTDS experiments to various environmental phenomena. References: 1. Haiping Lu, Stephanie A. McCartney, M. Chonde, D. Smyla, and Vlad Sadtchenko, Fast thermal desorption spectroscopy study of morphology and vaporization kinetics of polycrystalline ice films, J. Chem. Phys., 125, 044709, 2006. 2. Dash, J.G., A.W. Rempel and J.S. Wettlaufer, The physics of premelted ice and its geophysical consequences, Rev. Mod. Phys., 78, 695, 2006.

Lu, H.; McCartney, S.; Sadtchenko, V.

2007-12-01

247

Novel cation [N(SO2NMe3)2]+ and its synthesis and crystal structure. Dichloride of imido-bis(sulfuric) acid HN(SO2Cl)2. Part 1. Crystal structures of KN(SO2Cl)2.(1/2)CH3CN, KN(SO2Cl)2.(1/6)CH2Cl2, and [PCl4][N(SO2Cl)2].  

PubMed

Several salts of bis(chlorosulfonyl)imide HN(SO2Cl)2 (1), namely, two solvates of its potassium salt, KN(SO2Cl)2.(1/2)CH3CN (1K1), KN(SO2Cl)2.(1/6)CH2Cl2 (1K2), and its tetrachlorophosphonium salt, [PCl4][N(SO2Cl)2] (2), were prepared and structurally characterized. The reaction of HN(SO2Cl)2 with Me3N gives the [N(SO2Cl)2]- salt of a novel cation, [N(SO2NMe3)2]+. This cation is analogous to the [HC(SO2NMe3)2]+ cation, but in contrast to the latter, it is fairly stable to hydrolysis. The salt [N(SO2NMe3)2]+[N(SO2Cl)2]- (3) can be converted into salts of other anions by being treated with diluted aqueous solutions of the respective acids, and thus NO3-, Cl-.H2O, SeO3(2-), CH3COO-, HSO4-, (COO)2(2-) salts were prepared. Treatment of 3 with concentrated HNO3 gave the [N(SO2NMe3)2]+ [O2NO-H-ONO2]- salt, and the addition of an HCl-acidified FeCl3 aqueous solution yielded the FeCl4- salt. Methanolysis resulted in the formation of MeOSO3- and [MeOSO2NSO2OMe]- salts. All salts have been characterized by chemical analysis, vibrational spectroscopy, and X-ray structure determinations. PMID:16634603

Taraba, J; Zak, Z

2006-05-01

248

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

SciTech Connect

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

Hsu, S.A.

1995-04-01

249

Monitoring of volcanic SO2 emissions using the GOME-2 satellite instrument  

NASA Astrophysics Data System (ADS)

Volcanic eruptions are a major hazard to the local population near large volcanoes and to aviation. They also play an important role in global climate change. Atmospheric SO2 is an important indicator for volcanic eruptions and volcanic activity like passive degassing. Space based atmospheric sensors like GOME-2 on MetOp and OMI on EOS-Aura make it possible to detect the emissions of volcanic SO2 in near-real time (NRT) and monitor volcanic activity and eruptions on a global scale. This is important as satellites are often the first, and sometimes the only, source of information on volcanoes in remote locations because ground based monitoring is carried out only for a limited number of volcanoes. The GOME-2 instrument provides measurements of the SO2 columns with a spatial resolution of 80x40 km² and a global coverage within about one day. Volcanic sulfur dioxide emissions are routinely derived from solar backscatter measurements in the ultra-violet spectral range around 320 nm, applying the Differential Optical Absorption Spectroscopy (DOAS) method. This retrieval technique uses the high spectral resolution of the instruments to determine the total column density of SO2. DLR provides GOME-2 SO2 columns in NRT, i.e. less than two hours after sensing, which makes possible detection and tracking of volcanic eruption plumes as a valuable tool for aviation warning. Furthermore, the ability to monitor changes in volcanic degassing behavior is of great importance for early warning of volcanic activity, as large increases in SO2 fluxes are often an indicator for new episodes of volcanic unrest. As the standard DOAS method is restricted to optically thin conditions, current research activities focus on the use of a direct fitting algorithm for retrieving SO2 from GOME-2 data using shorter wavelength regions to achieve a higher sensitivity for low SO2 amounts typically observed in degassing situations. The GOME-2 measurements of volcanic SO2 are currently being used in the DUE/ESA project GlobVolcano that uses satellite monitoring to support early warning of volcanic risk and within the a new Volcano Fast Response System (Exupéry) developed within the framework of the German Geotechnology Program that includes both ground-based and space-based measurements of different volcanic parameters. In this contribution, we present exemplary results of SO2 retrieved from GOME-2 with DOAS and direct fitting approach, including analyses and comparisons for volcanic events. Further initial validation results for GOME-2 SO2 observations will be shown. Finally we will present the use of the operational GOME-2 SO2 data for early warning of volcanic hazards within GlobVolcano and the Exupéry system.

Rix, Meike; Valks, Pieter; van Gent, Jeroen; van Roozendael, Michel; Spurr, Robert; Hao, Nan; Emmadi, Sunil; Zimmer, Walter

2010-05-01

250

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

251

Sequential capture of CO2 and SO2 in a pressurized TGA simulating FBC conditions.  

PubMed

Four FBC-based processes were investigated as possible means of sequentially capturing SO2 and CO2. Sorbent performance is the key to their technical feasibility. Two sorbents (a limestone and a dolomite) were tested in a pressurized thermogravimetric analyzer (PTGA). The sorbent behaviors were explained based on complex interaction between carbonation, sulfation, and direct sulfation. The best option involved using limestone or dolomite as a SO2-sorbent in a FBC combustor following cyclic CO2 capture. Highly sintered limestone is a good sorbent for SO2 because of the generation of macropores during calcination/carbonation cycling. PMID:17533862

Sun, Ping; Grace, John R; Lim, C Jim; Anthony, Edward J

2007-04-15

252

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

253

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

254

Equilibrations of copper matte and fayalite slag under controlled partial pressures of SO 2  

Microsoft Academic Search

Equilibrium distributions of Cu, S and O between silica saturated fayalite slags and copper mattes (25 to 79 pct Cu) have\\u000a been examined experimentally under controlled partial pressures of SO2. The temperature range of the experiments was 1423 to 1573 K and pSO2 was varied between 0.1 and 1 atm. Concentrations of copper in the experimental slags were found to

Francisco J. Tavera; William G. Davenport

1979-01-01

255

Using horizontal transport characteristics to infer an emission height time series of volcanic SO2  

NASA Astrophysics Data System (ADS)

Characterizing the emission height of sulfur dioxide (SO2) from volcanic eruptions yields information about the strength of volcanic activity, and is crucial for the assessment of possible climate impacts and validation of satellite retrievals of SO2. Sensors such as the Ozone Monitoring Instrument (OMI) on the polar-orbiting Aura satellite provide accurate maps of the spatial distribution of volcanic SO2, but provide limited information on its vertical distribution. The goal of this work is to explore the possible use of a trajectory model in reconstructing both the temporal activity and injection altitude of volcanic SO2 from OMI column measurements observed far from the volcano. Using observations from the November 2006 eruption of Nyamuragira, back trajectories are run and statistical analyses are computed based on the distance of closest approach to the volcano. These statistical analyses provide information about the emission height time series of SO2 injection from that eruption. It is found that the eruption begins first injecting SO2 into the upper troposphere, between 13 km and 17 km, on November 28th 2006. This is then followed by a slow decay in injection altitude, down to 6 km, over subsequent days. The emission height profile is used to generate an optimal reconstruction based on forward trajectories and compared to OMI SO2 observations. The inferred altitude of the Nyamuragira SO2cloud is also compared to the altitude of sulfate aerosols detected in aerosol backscatter vertical profiles from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO).

Hughes, E. J.; Sparling, L. C.; Carn, S. A.; Krueger, A. J.

2012-09-01

256

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

257

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

Microsoft Academic Search

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

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

1992-01-01

258

The relationship between absorption of sulfur dioxide (SO 2 ) and inhibition of photosynthesis in several plants  

Microsoft Academic Search

Photosynthetic rate, transpiration rate and SO2 absorption rate were simultaneously measured under exposure to SO2 (0.1–1.0 ?l l\\u000a ?1) for 5 or 8 hr in six species belonging to C4 or C3 plants (Zea mays, Sorghum vulgare, Amaranthus tricolor, Oryza sativa, Avena sativa andHelianthus annuus). Distinct interspecific differences were found as to the extent of inhibition of photosynthetic rate. Calculation

Masahiko Katase; Tadahiro Ushijima; Tadayoshi Tazaki

1983-01-01

259

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

Microsoft Academic Search

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

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

2008-01-01

260

Kinetics of SO 2 absorption into fairly concentrated sulphuric acid solutions containing hydrogen peroxide  

Microsoft Academic Search

Absorption of SO2, diluted with nitrogen up to partial pressures of 500 Pa, was performed at 20°C and 1 atm with water and sulphuric acid solutions containing hydrogen peroxide in a cable contactor. The absorption rate was determined for various SO2 partial pressures and different concentrations of sulphuric acid (within the range 0–40 wt.%) and hydrogen peroxide in the scrubbing

Diane Thomas; Sandrine Colle; Jacques Vanderschuren

2003-01-01

261

Optical Emission Detection of SO2 by Microfabricated Inductively Coupled Plasma (mICP)  

Microsoft Academic Search

In this work a microfabricated ICP is used to optically detect trace amounts of SO_2. An mICP system consists of a planar microfabricated plasma source and miniature aluminum chamber and operates at 1-10 torr pressure and 0.7-3.5 W of 493 MHz RF power. An SO2 fraction as low as 2 ppm was measured using the intensity of atomic sulfur emission

Olga Minayeva; Jeffrey Hopwood

2001-01-01

262

SO2 gas monitoring by DOAS at Sakurajima and Suwanosejima volcanoes  

Microsoft Academic Search

Synopsis We have produced trial instrument for measurement of SO2 emission using differential optical absorption spectrometer (DOAS). Its performance has been tested at several volcanoes in Japan since 2003. The performance of the DOAS and its practice measurement were executed in Sakurajima and Suwanosejima. The SO2 emissions from Sakurajima and Suwanosejima were measured by the DOAS. Sakurajima emitted 500~1000ton\\/day due

Takehiko MORI; Kazuhiro ISHIHARA; Junichi HIRABAYASHI; Kouhei KAZAHAYA; Toshiya MORI

263

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

Microsoft Academic Search

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

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

2008-01-01

264

First In Situ Raman Study of Vanadium Oxide Based SO2 Oxidation Supported Molten Salt Catalysts  

Microsoft Academic Search

In situ Raman spectroscopy at temperatures up to 500?°C is used for the first time to identify vanadium species on the surface of a vanadium oxide based supported molten salt catalyst during SO2 oxidation. Vanadia\\/silica catalysts impregnated with Cs2SO4 were exposed to various SO2\\/O2\\/SO3 atmospheres and in situ Raman spectra were obtained and compared to Raman spectra of unsupported “model”

I. Giakoumelou; R. M. Caraba; V. I. Parvulescu; S. Boghosian

2002-01-01

265

SO(2,C) invariant discrete gauge states in liouville gravity coupled to minimal conformal matter  

NASA Astrophysics Data System (ADS)

We construct the general formula for a set of discrete gauge states (DGS) in c < 1 Liouville theory. This formula reproduces the previously found c = 1 DGS in the appropriate limiting case. We also demonstrate the SO(2,C) invariant structure of these DGS in the old covariant quantization of the theory. This is in analogy to the SO(2,C) invariant ring structure of BRST cohomology of the theory.

Lee, Jen-Chi

266

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

267

Yield response curves of crops exposed to SO 2 time series  

NASA Astrophysics Data System (ADS)

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

Male, Larry; Preston, Eric; Neely, Grady

268

Upper tropospheric SO2 conversion into sulfuric acid aerosols and cloud condensation nuclei  

Microsoft Academic Search

We have investigated the potential of upper tropospheric cloud condensation nuclei (CCN) formation from sulfur dioxide. This process involves three steps including SO2 conversion to gaseous sulfuric acid (GSA), homogeneous bimolecular nucleation of GSA and water vapor leading to new aerosol particles, and new aerosol particle growth via mutual coagulation and GSA-H2O condensation. Our investigation includes both measurements of SO2

Ari Laaksonen; Liisa Pirjola; Markku Kulmala; Karl-Heinz Wohlfrom; Frank Arnold; Frank Raes

2000-01-01

269

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

270

Reaction of SO2 with stoichiometric and defective NiO(100) surfaces  

Microsoft Academic Search

The interaction of SO2 with both stoichiometric and defective NiO(100) surfaces has been studied by x-ray photoemission spectroscopy, ultraviolet photoemission spectroscopy, Auger-electron spectroscopy, and low-energy electron diffraction. Surface defects are found to play an important role in chemisorption. SO2 interacts only weakly with the stoichiometric NiO(100) surface at room temperature. The adsorption that does occur yields adsorbates having direct S-O

Xiaomei Li; Victor E. Henrich

1993-01-01

271

Short-term Temporal Variability of SO2 Emissions at White Island, New Zealand  

Microsoft Academic Search

A new installation of a scanning mini-DOAS system at White Island Volcano in New Zealand in late June, 2006 allowed for SO2 emission data to be collected on a semi-continuous basis (see also Miller et al., this session). Given the appropriate wind direction and wind velocity data, a SO2 emission rate estimate can be calculated approximately every four minutes. Analysis

C. Werner; C. Miller; M. Edmonds

2006-01-01

272

Effects of carbonaceous particles and heavy metals on mortar-SO 2 reactions  

Microsoft Academic Search

The effects of carbonaceous particles and heavy metals in the interaction between sulfur dioxide and mortars were investigated\\u000a in a laboratory exposure system. Simulation experiments were carried out in a flow chamber where temperature, relative humidity\\u000a and SO2 concentration were controlled. Samples of lime, pozzolan and cement mortars were exposed for 150 days in air with 3 ppm of\\u000a SO2

G. Zappia; C. Sabbioni; G. Gobbi

1998-01-01

273

Degassing at Anatahan volcano during the May 2003 eruption: Implications from petrology, ash leachates, and SO2 emissions  

NASA Astrophysics Data System (ADS)

On 10 May 2003, Anatahan volcano (located at 16°21? N 145°40? E on the Mariana arc) entered its first historical eruptive episode, sending ash to > 12 km into the atmosphere. Abundant accretionary lapilli, quenched pumice textures, and hydrothermal minerals in the earliest eruptive deposits indicate hydromagmatic interaction and active mining of the pre-eruptive hydrothermal system. Whole-rock compositions of the products erupted within the first week are chemically homogenous, with SiO2 ˜61%, MgO ˜2.1%, K2O ˜1.4%, Na2O ˜4.1% and Fe2O3 ˜9.1%. The products are classified as medium-K andesites with tholeiitic affinity. Slightly more silicic matrix glass compositions (up to 63% SiO2 in microlite-rich matrices) overlap with whole rock, suggesting limited crystal fractionation with microlite crystallization responsible for the more evolved residual melt. Decreasing corrected LOI values (2.3 1.4 wt.%) upsection are consistent with waning hydrothermal mineral contributions as the eruption progressed. Oxygen fugacity calculations based on the ferric to ferrous iron ratio of bulk samples indicate an oxidized magma with ?NNO ˜+1. Two-pyroxene equilibrium thermometry suggests magmatic temperatures of 1050 1100 °C. Matrix glass volatile contents show a degassed residual melt, with < 0.5 wt.% H2O, 1000 2000 ppm Cl, 480 780 ppm F, 50 150 ppm S, and < 5 ppm CO2. A magmatic SO2 flux of 3 4.5 kt/day was measured by COSPEC on 21 May. Ash leachate data indicate a decreasing S/Cl ratio (3.3 0.7) in the eruptive plume between 10 and 21 May, with a relatively constant Cl concentration. Assuming a constant Cl flux, an SO2 flux of 14 22 kt/day is calculated for 10 May. The average S concentration from ash leachates (1230 mg/kg) suggests that at least 25% of the SO2 (˜60 kt) erupted from Anatahan between 10 and 21 May was removed from the plume by the precipitation of sulphate salts in the eruption column, adsorbtion onto ash particles and subsequent deposition. Molar ratios in ash leachates elucidate CaSO4 and NaCl as the most likely soluble salts formed in the plume. Total element abundances, molar S/Ca > 1 and Ca, Mg, Na, and K ratios in the leachates suggest a hydrothermal fluid contribution to elements present as water soluble salts adsorbed onto ash. Sulfur budget calculations based on estimates of pre-eruptive magmatic and residual melt S contents, mass of erupted magma, and total SO2 output fluxes require an additional source of S other than the erupted magma. Multiple lines of evidence, including high SO2 emissions early in the eruption, the presence of accretionary lapilli and hydrothermal minerals in the early eruptive deposits, quenched pumice textures, and cation and anion ratios and abundances in ash leachates suggest that a S-rich free volatile phase exsolved from a large magma body. Magmatic volatiles were stored as components of the hydrothermal system (pressurized gases, hydrothermal fluids, and/or hydrothermal minerals) to be remobilized early in the eruption to contribute to the total SO2 output.

de Moor, J. M.; Fischer, T. P.; Hilton, D. R.; Hauri, E.; Jaffe, L. A.; Camacho, J. T.

2005-08-01

274

Simultaneous absorption of NO and SO2 into hexamminecobalt(II)/iodide solution.  

PubMed

An innovative catalyst system has been developed to simultaneously remove NO and SO2 from combustion flue gas. Such catalyst system may be introduced to the scrubbing solution using ammonia solution to accomplish sequential absorption and catalytic oxidation of both NO and SO2 in the same reactor. When the catalyst system is utilized for removing NO and SO2 from the flue gas, Co(NH3)(6)2+ ions act as the catalyst and I- as the co-catalyst. Dissolved oxygen, in equilibrium with the residual oxygen in the flue gas, is the oxidant. The overall removal process is further enhanced by UV irradiation at 365 nm. More than 95% of NO is removed at a feed concentration of 250-900 ppm, and nearly 100% of SO2 is removed at a feed concentration of 800-2500 ppm. The sulfur dioxide co-existing in the flue gas is beneficial to NO absorption into hexamminecobalt(II)/iodide solution. NO and SO2 can be converted to ammonium sulfate and ammonium nitrate that can be used as fertilizer materials. The process described here demonstrates the feasibility of removing SO2 and NO simultaneously only by retrofitting the existing wet ammonia flue-gas-desulfurization (FGD) scrubbers. PMID:15811409

Long, Xiang-Li; Xiao, Wen-De; Yuan, Wei-kang

2004-12-21

275

Direct Observation of Reversible and Irreversible Stomatal Responses of Attached Sunflower Leaves to SO2  

PubMed Central

The effects of SO2 on stomatal aperture of attached sunflower leaves were observed with a remote-control light microscope system that permitted continuous observation of stomatal responses over periods of several hours. The relationship between actual stomatal aperture and stomatal conductance, measured with a porometer, also was examined on leaves before and after exposure to SO2. A distinction between uninjured and injured regions was clearly visible on leaves after exposure to 1.5 microliters per liter SO2 for less than an hour. During the exposure, the mean value of apertures for many stomata, which indicates stomatal conductance and transpiration rate, tended to decrease simultaneously in the uninjured and injured regions. However, the rate of decrease in the injured region was slower than that in the uninjured region because of a transient opening induced by water-soaking in the injured region. The transient opening was less common in stomata near veins and veinlets. There was a good correlation between pore width and stomatal conductance measured with a porometer before exposure to SO2. This correlation continued in leaves exposed to SO2 until visible, irreversible injury occurred, but then it disappeared. The results of these experiments indicate the necessity of continuous observation of individual stomata under the microscope to understand the effects of air pollutants such as SO2 on stomatal behavior. Images Fig. 3 Fig. 5

Omasa, Kenji; Hashimoto, Yasushi; Kramer, Paul J.; Strain, Boyd R.; Aiga, Ichiro; Kondo, Jiro

1985-01-01

276

Horizontal and Vertical Distribution of SO2 in the Venus Clouds From SPICAV UV spectrometer.  

NASA Astrophysics Data System (ADS)

The two bands of UV absorption of SO2 at 180-220 and 280-300 nm may be used to detect SO2 in the upper atmosphere of Venus. On board Venus Express mission, the UV spectrometer (118 - 320 nm, resolution 1.5 nm) of SPICAV is dedicated to nadir viewing, limb viewing and vertical profiling by stellar and solar occultation. In the solar occultation mode, SO2 is seen up to 100 km with a mixing ratio of about 1 ppmv, a puzzling result since it should be photo-dissociated at this altitude. In the stellar occultation mode which is performed at night, SO2 is also seen up to 100 km, possibly resulting from the evaporation of H2SO4 cloud droplets. In nadir orientation, SPICAV UV analyzes the albedo spectrum (solar light scattered back from the clouds) to retrieve SO2, and the distribution of the UV-blue absorber (of still unknown origin) on the day side with implications for cloud structure, and atmospheric dynamics. The abundance of SO2 and its scale height are determined by comparison of the measured albedo spectrum with the output of a radiative transfer code, yielding horizontal distributions. Results obtained from the various modes of observation will be compared.

Bertaux, J.; Bertaux, E.; Montmessin, F.

2008-12-01

277

The SO2 plume over the eastern US: Remote and in situ observations  

NASA Astrophysics Data System (ADS)

Using information sensed from satellites to understand regional air quality problems shows great potential, but poses great challenges. The sources and distribution of SO2 over eastern North America may be areas where remote sensing can provide a powerful tool to improve our understanding. In the Eastern US, substantial amounts of high-sulfur coal are still burned without effective pollution controls. The resulting sulfur dioxide generates sulfate haze composed of fine particles. These particles contribute to reduced visibility and climate forcing. For several years, we have been using pulsed fluorescence instruments to measure tropospheric SO2 concentrations at a ground station and from a small research aircraft. Hundreds of individual profiles have been obtained, and above ground plumes of SO2 frequently exceed 10 ppbv. Aircraft measurements alone, however, cannot uncover the extent of the pollution. The UV-visible spectra collected by the Global Ozone Monitoring Experiment (GOME) can be analyzed for column SO2 content. We present comparisons of remotely sensed and in situ aircraft measurements (altitude-integrated column content) of SO2 to evaluate the satellite data and to determine whether GOME measurements can be useful in studies of individual smog/haze episodes. Results confirm the existence of large-scale SO2 plumes and a strong seasonal cycle. See http://www.meto.umd.edu/~umdair/rammpp01.html and http://www.iup.physik.uni-bremen.de/gome/

Dickerson, R. R.; Doddridge, B. G.; Hains, J. C.; Marufu, L.; Burrows, J. P.; Richter, A.

2003-04-01

278

The NOAA Near Real-time OMI-SO2 Cloud Visualization and Product Distribution System  

NASA Astrophysics Data System (ADS)

The Ozone Monitoring Instrument (OMI) on the NASA EOS/Aura research satellite allows measurement of SO2 concentrations at UV wavelengths with daily global coverage. SO2 is detected from space using its strong absorption band structure in the near UV (300-320 nm) as well as in IR bands near 7.3 and 8.6 mm. Thirty years of UV SO2 measurements with the Total Ozone Mapping Spectrometer (TOMS) and OMI sensors have shown that the highest concentrations of SO2 occur in volcanic clouds produced by explosive magmatic eruptions, which also emit ash. However, icing of ash particles in water-rich eruption clouds, and/or suppression of the IR split- window signal by ambient water vapor or cloud opacity can inhibit direct detection of ash from space. Large SO2 concentrations are therefore a reliable indicator of the presence of airborne volcanic ash. UV SO2 measurements are very robust and are insensitive to the factors that confound IR data. SO2 and ash can be detected in a very fresh eruption cloud due to sunlight backscattering and ash presence can be confirmed by UV derived aerosol index measurements. The lack of other large point sources of SO2 facilitates development and implementation of automated searches for volcanic clouds with a very low false alarm rate. The NASA Earth Sciences Applications Office has funded a cooperative agreement between UMBC, NOAA, GSFC, and USGS to infuse research satellite SO2 data products into volcanic hazard Decision Support Systems (DSSs) operated by the National Oceanic and Atmospheric Administration (NOAA) and the US Geological Survey (USGS). This will provide aviation alerts to the Federal Aviation Administration (FAA), that will reduce false alarms and permit more robust detection and tracking of volcanic clouds, and includes the development of an eruption alarm system, and potential recognition of pre-eruptive volcanic degassing. Near real-time (NRT) observations of SO2 and volcanic ash can therefore be incorporated into data products compatible with Decision Support Tools (DSTs) in use at Volcanic Ash Advisory Centers (VAACs) in Washington and Anchorage, and the USGS Volcano Observatories. In this poster we show the latest NOAA Office of Satellite Data Processing and Distribution (OSDPD) development of an online NRT image and data product distribution system that generates eruption alarms, allows the extraction of volcanic cloud subsets for special processing, and provides access to analysis tools and graphical products. Products are infused into DSTs including the Volcanic Ash Coordination Tool (VACT), under development by the NOAA Forecast Systems Laboratory and the FAAs Oceanic Weather Product Development Team (OWPDT), to monitor and track, drifting volcanic clouds.

Vicente, G.; Serafino, G.; Krueger, A.; Carn, S.; Yang, K.; Krotkov, N.; Guffanti, M.; Levelt, P.

2007-12-01

279

Simultaneous sampling of NH 3, HNO 3, HC1, SO 2 and H 2O 2 in ambient air by a wet annular denuder system  

NASA Astrophysics Data System (ADS)

A new sampling device is described for the simultaneous collection of NH 3, HNO 3, HCl, SO 2 and H 2O 2 in ambient air. The apparatus is based on air sampling by two parallel annular denuder tubes. The gases are collected by absorption in solutions present in the annulus of the denuder tubes. After a sampling time of 30 min at flow rate of 32 ? min -1 the solutions are extracted from the denuders and analyzed off-line. The detection limits of NH 3, HNO 3, HCL and SO 2 are in the order of 0.1-0.5 ?m -3. For H 2O 2 the detection limit is 0.01 ?m -3. The reproducibility is 5-10% at the level of ambient air concentrations. Comparison of this novel technique with existing methods gives satisfactory results. The compact set-up offers the possibility of field experiments without the need of extensive equipment.

Keuken, Menno P.; Schoonebeek, Carlo A. M.; van Wensveen-Louter, Annet; Slanina, Jakob

280

SO2 measurements at Venus' cloud top: from Pioneer Venus Orbiter to Venus Express  

NASA Astrophysics Data System (ADS)

This talk will focus on UV nadir measurements of SO_2 at Venus cloud top level obtained with SPICAV/Venus Express from 2006 to 2010, using an expanded data set and updated version of Marcq et al. [2008] radiative transfer algorithm. Provisional results show a more complicated picture than thought based on the first 300 Venus Express orbits [Marcq et al., 2011; Belyaev et al., 2008]. Short-term variability as well as maximal values seem on par with 1980s UVS/Pioneer Venus data [Esposito et al., 1988], confirming the halt of the negative trend in SO_2 mean abundance observed in the 1980s and 1990s. Latitudinal gradient is usually negative, but positive in a handful of orbits, reminiscent of the situation in the 1980s [Zasova et al., 1993; Na et al., 1994]. This may point to frequent changes in the relative intensity of the processes ruling SO_2 abundance at cloud top level, leading to at least two distinct regimes for SO_2 with opposite latitudinal gradients. A positive correlation between the mean UV brightness (proxy for unknown UV absorber) and SO_2 mixing ratio has also been evidenced. Naive transport modeling as well as much more sophisticated chemical modeling [Krasnopolsky, 2012] seem able to reproduce much of the observed spatial and temporal variability of SO_2, indicating at least a qualitative understanding of the physical and chemical process at work. All these results will be compared when relevant to the band ratio SO_2 retrievals from Pioneer Venus era [Esposito et al., 1988] in order to investigate possible changes on a decadal timescale in Venus' lower mesosphere.

Marcq, Emmanuel; Belyaev, Denis; Montmessin, Franck; Bertaux, Jean-Loup; Fedorova, Anna

2012-07-01

281

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

282

Satellite monitoring of volcanic SO2 emissions within the Volcano Fast Response System (Exupéry)  

NASA Astrophysics Data System (ADS)

Volcanic eruptions are a major hazard to the local population near large volcanoes and to aviation. They also play an important role in global climate change. Atmospheric SO2 is an important indicator for volcanic eruptions and volcanic activity like passive degassing. Space based atmospheric sensors such as GOME-2 on MetOp and OMI on EOS-Aura make it possible to detect the emissions of volcanic SO2 in near-real time (NRT) and monitor volcanic activity and eruptions on a global scale. The GOME-2 instrument provides operational measurements of the SO2 columns with a spatial resolution of 80x40 km² and a global coverage within about one day. Volcanic sulfur dioxide emissions are determined from solar backscatter measurements in the ultra-violet spectral range between 315 - 326 nm, applying the Differential Optical Absorption Spectroscopy (DOAS) method. This retrieval technique uses the high spectral resolution of the instrument to determine the total column density of SO2. The ability to monitor changes in volcanic degassing behavior is of great importance for early warning of volcanic activity, as large increases in SO2 fluxes are often an indicator for new episodes of volcanic unrest. Ensembles of backward trajectories using the FLEXTRA model are applied to relate exceptional SO2 values to particular sources or regions and hence attribute them to a volcanic or anthropogenic origin. Trajectory density maps give an overview of the most probable location of the emission source. Additionally, the moment of the eruption as well as the emission and the plume height can be estimated. Hypothetical forward trajectories starting at potentially active volcanoes allow forecasting the dispersion of volcanic SO2 and ash depending on the emission height in case of an eruption. For validation purposes the dispersion model FLEXPART provides a three dimensional forecast of the plume motion and the transport of SO2 for several days. The GOME-2 observations of volcanic SO2 are used in a new Volcano Fast Response System (Exupéry) developed within the framework of the German Geotechnology Program that includes both ground-based and space-based measurements of different volcanic parameters. The daily GOME-2 SO2 data as well as hypothetical trajectories and probability density maps are supplied to a database approximately 7 hours after the measurement and displayed in a GIS system that can be accessed by local authorities and observatories to provide additional information in the case of volcanic unrest. In this contribution we present exemplary results of GOME-2 SO2 observations and the trajectory matching technique for recent volcanic eruptions. Further we will present initial validation results for GOME-2 SO2 data using ground-based measurements in combination with other satellite observations, as well as dispersion modeling. We will focus on the use of the GOME-2 SO2 data and model results within the Exupéry project.

Rix, Meike; Maerker, Cordelia; Valks, Pieter; Erbertseder, Thilo

2010-05-01

283

Observing the plume of Popocatepetl with a novel SO2-Camera  

NASA Astrophysics Data System (ADS)

Sulfur dioxide flux emission measurements can be an important tool for monitoring volcanoes and eruption risk assessment. For instance hanges in the SO2 flux have been recorded prior to volcanic eruptions. The SO2 camera is a novel technique for the remote sensing of volcanic emissions based on measuring the ultra-violet absorption of SO2 in a narrow wavelength window around 310 nm by employing band-pass interference filters and a 2-D UV-sensitive CCD detector. Solar radiation scattered in the atmosphere is used as a light source for the measurements. The effect of aerosol scattering can be eliminated by additionally measuring the incident radiation around 325 nm where the absorption of SO2 is no longer significant, thus rendering the method applicable to optically opaque plumes. The ability to deliver spatially resolved images of volcanic SO2 distributions at a frame rate on the order of 1 Hz makes the SO2 camera a very promising technique for volcanic monitoring. The high time resolution allows the calculation of the wind-speed directly from the measurements, thus largely eliminating the main error source of flux measurements. Another advantage of the high time resolution is the possibility to correlate the gas flux with other data sets on shorter timescales. Here we present results of a measurement campaign conducted at Popocatepetl, Mexico in April 2010, which were performed with a new prototype of a SO2 camera incorporating an additional Differential Optical Absorption Spectroscopy (DOAS) system. The DOAS system was used to test a new calibration method, besides that it allows to correct for radiative transfer effects. The built in DOAS system carried out point measurements of the volcanic plume in a region that corresponds to the center of the SO2 camera images. This yields column density / apparent absorption pairs that can be used to determine the calibration curve for the SO2 camera images. In order to test and validate this approach simultaneous measurements with an imaging-DOAS, were conducted. The imaging-DOAS two dimensional trace gas distributions were used to verify the camera calibration.

Luebcke, P.; Zielcke, J.; Vogel, L.; Kern, C.; Bobrowski, N.; Platt, U.

2010-12-01

284

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

285

TiO2-Based Gas Sensor: A Possible Application to SO2.  

PubMed

Fixation of SO2 molecules on anatase TiO2 surfaces with defects have been investigated by first-principles density functional theory (DFT) calculations and in situ Fourier transform infrared (FTIR) surface spectroscopy on porous TiO2 films. Intrinsic oxygen-vacancy defects, which are formed on TiO2(001) and TiO2(101) surfaces by ultraviolet (UV) light irradiation and at elevated temperatures, are found to be most effective in anchoring the SO2 gas molecules to the TiO2 surfaces. Both TiO2(101) and TiO2(001) surfaces with oxygen vacancies are found to exhibit higher SO2 adsorption energies in the DFT calculations. The adsorption mechanism of SO2 is explained on the basis of electronic structure, charge transfer between the molecule and the surface, and the oxidation state of the adsorbed molecule. The theoretical findings are corroborated by FTIR experiments. Moreover, the (001) surface with oxygen vacancies is found to bind SO2 gas molecules more strongly, as compared to the (101) surface. Higher concentration of oxygen vacancies on the TiO2 surfaces is found to significantly increase the adsorption energy. The results shed new insight into the sensing properties of TiO2-based gas sensors. PMID:23915321

Nisar, Jawad; Topalian, Zareh; De Sarkar, Abir; Osterlund, Lars; Ahuja, Rajeev

2013-08-20

286

Sorbent/urea slurry injection for simultaneous SO2/NOx removal  

SciTech Connect

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 reactant/pollutant stoichiometric ratios of 2 and 1, respectively. SO2 emission reductions from slurry injection were enhanced compared with dry Ca(OH)2 sorbent injection methods, possibly due to sorbent fracturing to smaller, more reactive particles. Emissions from NH3 slip and N2O formation were reduced in comparison with others' published results while similar NOx reductions were obtained. The injection of the urea-based solution enhanced the SO2 removal, likely due to the formation of a (NH4)2Ca(SO4)2 (center dot) H2O compound. The results of the pilot-scale study have shown high reduction of both SO2 and NOx, suggesting the need for full-scale studies to further assess the combined sorbent/urea-based slurry injection technology.

Gullett, B.K.; Bruce, K.R.; Hansen, W.F.; Hofmann, J.E.

1992-01-01

287

SO2 Emissions to the Atmosphere from Active Volcanoes in Northern Central America, 2000-2002  

NASA Astrophysics Data System (ADS)

We have made ground-based and aircraft COSPEC measurements at the principal active volcanoes in Guatemala (Tacana, Santiaguito, Fuego, and Pacaya) and El Salvador (Santa Ana and San Miguel) during the past three years, as part of an attempt to measure baseline SO2 emissions of potentially dangerous volcanoes and to calibrate satellite based SO2 retrievals using MODIS and ASTER. Two of the volcanoes measured (Tacana and Santa Ana) are likely venting hydrothermal systems, while the others (Santiaguito, Fuego, Pacaya, and San Miguel) are in open vent condition. Only Pacaya is emitting high fluxes of SO2 (>1000 tonnes/day) while the other vents are much lower emitters (20-300 tonnes/day in general). Measurements at Fuego, whose most recent fluxes were measured during its current active phase, are likely to reflect eruption rates of basaltic lava, while those at Pacaya may reflect a large circulating and convecting high level chamber. A larger number of volcanoes in the same region are considered active but do not emit gas as part of an identifiable plume. They may be degassing into hydrothermal systems or gas traps. Both MODIS and ASTER have archives of satellite based multispectral IR data that are being used for SO2 flux determinations and comparison and correlation with ground-based measurements. Although not analyzed at abstract time, we expect to show examples to compare with our COSPEC data to assess the ability of these new sensors for low-level SO2 measurements from space.

Rodriguez, L. A.; Branan, Y. K.; Watson, M.; Bluth, G. J.; Rose, W. I.; Chigna, G.; Matias, O.; Coy, A.; Fischer, T.; Carn, S. A.

2002-05-01

288

The importance of soot particles and nitrous acid in oxidizing SO 2 in atmospheric aqueous droplets  

NASA Astrophysics Data System (ADS)

Soot particles catalyze the oxidation of SO 2 H 2O, HSO 3-, and SO 2-3 species at the same rate; however, the rate of production of sulfate is not constant at a constant partial pressure of SO 2. The rate decreases as the pH decreases because the total concentration of S(IV) in aqueous droplets decreases as the pH decreases. The sulfate production rate has a complex dependence on the concentration of S(IV) and is not very sensitive to a change in SO 2 concentration at normal atmospheric conditions. The oxidation of SO 2 by HNO 2 in atmospheric water droplets first produces hydroxylamine disulfonate, which undergoes acid-catalyzed hydrolysis to form sulfate and hydroxylamine monosulfonate. The latter can react with HNO 2 and would then end up as nitrous oxide and sulfate Model calculations have been made comparing the relative importance of the sulfate production mechanism by soot particles and nitrous acid with other mechanisms involving liquid water. The results indicate that both soot and HNO 2 mechanisms can be very important when the lifetime of the atmospheric aqueous droplets is long.

Chang, S. G.; Toossi, R.; Novakov, T.

289

Erosion and modification of SO2 ice by ion bombardment of the surface of Io  

NASA Astrophysics Data System (ADS)

New measurements on the effect of slow ion bombardment of SO2 ice using Ar(+) in the 15-45 keV range are presented. Total yields for loss of SO2 are given along with the energy spectra of the ejected molecules and molecular fragments and information on the chemical changes induced by the ion bombardment. These data are used to estimate that the direct sputter ejection rate of sulfur into the Jovian plasma is of the order of 10 billion atoms/sq cm/s, that the erosion rate of fresh SO2 deposits due to sputtering is of the order of 0.001 cm/yr, and that a significant and possibly observable column density of SO3 can be produced in an SO2 front only for penetrating ion bombardment. Chemical activity occurs even in rather low-temperature SO2 ice bombardment by ions in the nuclear stopping region, and this activity is likely to increase with increasing temperature.

Johnson, R. E.; Garrett, J. W.; Boring, J. W.; Barton, L. A.; Brown, W. L.

1984-02-01

290

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

2012-12-20

291

Observations and Comparison of SO2 Measurements Aboard the NOAA P-3 during ARCPAC  

NASA Astrophysics Data System (ADS)

Instrument inter-comparisons play a crucial role in the successful execution of atmospheric measurement campaigns. The ability to quantify agreement among instruments that measure atmospheric compounds lends credence to the individual measurements and extends the scope of the overall study. One such measurement is that of sulfur dioxide (SO2). SO2 is the predominant anthropogenic sulfur- containing air pollutant. It plays an important role in the atmospheric sulfur cycle through its contribution to acidic aerosol formation, aerosol and cloud droplet modification, and acidic precipitation. Due to its large indirect impact on climate it is important to precisely know its sources, sinks and its atmospheric distribution. A modified TECO 43C-TL pulsed fluorescence instrument and a Chemical Ionization Mass Spectrometer (CIMS), were both deployed aboard the NOAA P-3 aircraft to measure SO2 during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC) field program. The detection technique, sampling configuration, and calibration methods of the instruments are described. The performance of each instrument is assessed using ambient data to examine detection sensitivity, background signal, and time response. Lastly, an evaluation of the comparative performance of the two measurements is presented, as are preliminary results examining both the Arctic SO2 distribution observed from the NOAA P-3 and SO2 emissions from the Fairbanks urban area.

Nowak, J. B.; Holloway, J. S.; Neuman, J. A.; Fehsenfeld, F. C.

2008-12-01

292

Solar absorption Fourier Transform Infrared spectroscopy applied to detect SO2 plumes above Mexico City  

NASA Astrophysics Data System (ADS)

There are sources of emissions of sulfur dioxide (SO2) that disperse to the Metropolitan Area of Mexico City (MCMA). The sources can be divided into three categories: a) The active Popocatepetl volcano located 70 km SE from the center of Mexico City, b) the industrial area located approximately 70 km to the and c) other local sources located in the surroundings from the measurement.. Solar absorption infrared spectra are being recorded since 2007 above the campus of the Universidad Nacional Autónoma de México (UNAM, 19.33 N, 99.18 W, 2260 m.a.s.l.). The column of SO2 was retrieved from all the spectra recorded in 2008 with the retrieval code SFIT2. Enhancement of the SO2 column could be identified in different time periods. The origin of the detected SO2 is determined by correlating the SO2 column with a) its surface concentration measured in the surroundings by the monitoring stations from the city’s monitoring network of (RAMA), b) the height of the mixing layer measured at UNAM, and c) meteorological wind data (REDMET, NCEP-NARR, and SMN). The result shows that the extraordinary events are correlated with the mentioned sources, and the analysis confirms prior studies that the plume travels at different altitudes. The plume of the Popocatepetl volcano is transported according to the wind at 5000 m.a.s.l. while emissions from the industrial area northwest of the MCMA are dispersed at lower altitudes within the mixing layer.

Aldana-Vazquez, A.; Stremme, W.; Grutter, M.

2010-12-01

293

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

294

SO2 Reaction on Cu(100): SO3 Structure and Formation —Density Functional Theory Investigation—  

NASA Astrophysics Data System (ADS)

SO3 structure and reaction on Cu(100) were investigated by using density functional theory-based calculation. SO3 was found to adsorbed on the surface through its three oxygen atoms having a trigonal pyramid structure with its C3v axis lying nearly perpendicular to the surface. The interaction of SO3 with the surface was found to occur at the dz2 surface orbital that led to the delocalization of SO3 molecular orbitals. This delocalization resulted in the elongation of one S-O bondlength. The barrier for the reaction SO2+O?SO3 was found to be 0.2 eV, smaller than the one for reaction SO2?SO+O which indicate that the SO2+O?SO3 should be more favorable to occur.

Agusta, Mohammad Kemal; David, Melanie; Nakanishi, Hiroshi; Kasai, Hideaki

2008-08-01

295

TiO2 nanotube array sensor for detecting the SF6 decomposition product SO2.  

PubMed

The detection of partial discharge through analysis of SF(6) gas components in gas-insulated switchgear, is significant for the diagnosis and assessment of the operating state of power equipment. The present study proposes the use of a TiO(2) nanotube array sensor for detecting the SF(6) decomposition product SO(2), and the application of the anodic oxidation method for the directional growth of highly ordered TiO(2) nanotube arrays. The sensor response of 10-50 ppm SO(2) gas is tested, and the sensitive response mechanism is discussed. The test results show that the TiO(2) nanotube sensor array has good response to SO(2) gas, and by ultraviolet radiation, the sensor can remove attached components very efficiently, shorten recovery time, reduce chemical poisoning, and prolong the life of the components. PMID:22737009

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

2012-03-07

296

Bis (trifluoromethyl) sulfone, CF3SO2CF3: Synthesis, vibrational and conformational properties  

NASA Astrophysics Data System (ADS)

Bis (trifluoromethyl) sulfone, CF3SO2CF3, was obtained as a byproduct in the synthesis of CF3SO2SCF3. The compound was characterized by infrared and Raman spectroscopy as well quantum chemical calculations. Quantum mechanical calculations indicate the possible existence of two conformers symmetrically equivalent with C2 symmetry. The preference for the staggered form was studied using the total energy scheme and the natural bond orbital (NBO) partition scheme. Additionally, the total potential energy was deconvoluted using a sixfold decomposition in terms of a Fourier-type expansion, showing that the hyperconjugative effect was dominant in stabilizing the staggered conformer. Infrared and Raman spectra of CF3SO2CF3 were obtained. Harmonic vibrational wavenumbers and a scaled force field were calculated, leading to a final root mean-square deviation of 7.8 cm-1 when comparing experimental and calculated wavenumbers.

Defonsi Lestard, M. E.; Ramos, L. A.; Tuttolomondo, M. E.; Ulic, S. E.; Ben Altabef, A.

2012-10-01

297

SO(2) protects the amino nitrogen metabolism of Saccharomyces cerevisiae under thermal stress.  

PubMed

Thermal stress conditions during alcoholic fermentation modify yeasts' plasma membrane since they become more hyperfluid, which results in a loss of bilayer integrity. In this study, the influence of elevated temperatures on nitrogen metabolism of a Saccharomyces cerevisiae strain was studied, as well as the effect of different concentrations of SO(2) on nitrogen metabolism under thermal stress conditions. The results obtained revealed that amino nitrogen consumption was lower in the fermentation sample subjected to thermal stress than in the control, and differences in amino acid consumption preferences were also detected, especially at the beginning of the fermentation. Under thermal stress conditions, among the three doses of SO(2) studied (0, 35, 70?mg?l(-1) SO(2) ), the highest dose was observed to favour amino acid utilization during the fermentative process, whereas sugar consumption presented higher rates at medium doses. PMID:22452834

Ancín-Azpilicueta, Carmen; Barriuso-Esteban, Blanca; Nieto-Rojo, Rodrigo; Aristizábal-López, Nerea

2012-03-27

298

Reconstruction of volcanic SO2 flux emission chronology from space-based measurements  

NASA Astrophysics Data System (ADS)

A single satellite image framing a volcanic cloud can be regarded as recording the evolution in time of physical and volcanological parameters, effectively capturing many hours of volcanic activity, while a collection of images can offer a valuable record of an entire volcanic eruption process. Here we discuss how SO2 flux time series can be reconstructed using SO2 amount maps retrieved from MODIS infrared images and wind speeds from a meteorological model. Results of this procedure applied to the 2006 Mt. Etna eruption's MODIS data are compared with SO2 flux time series measured by the ground-based FLAME network of UV DOAS instruments surrounding the volcano. We show that quantitative reconstruction of flux time series from satellite data is feasible and that this approach represents a new tool useful to interpret volcanic processes, in particular in poorly monitored remote locations.

Merucci, L.; Burton, M. R.; Corradini, S.; Salerno, G. G.

2011-12-01

299

TiO2 Nanotube Array Sensor for Detecting the SF6 Decomposition Product SO2  

PubMed Central

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

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

2012-01-01

300

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

SciTech Connect

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, was achieved. SO2 emission reductions from slurry injection were enhanced moderately when compared with dry sorbent injection methods, possibly caused by sorbent fracturing to smaller, more reactive particles. Emissions from ammonia (NH3) slip (unreacted nitrogen-based reducing agent) and nitrous oxide (N2O) formation were reduced in comparison with other published results, while similar NOx reductions were obtained.

Bruce, K.R.; Hansen, W.F.

1993-09-01

301

Gas-phase nucleophilic reactions in SO 2F 2: experiment and theory  

NASA Astrophysics Data System (ADS)

The gas-phase ion-molecule reactions of simple anions (HO -, CH 3O -, NH 2-) with SO 2F 2 proceed with rate constants close to the collision limit. The energy surface for the OH -/SO 2F 2 reaction has been characterized by ab initio calculations using basis functions adapted for a pseudopotential and corrected for anionic systems by the generator coordinate method (GCM) at the QCISD(T)/(ECP/TZV/GCM) level. The calculations indicate that reaction occurs by initial addition of the anion to SO 2F 2 to form a hypervalent sulfur species. The high efficiency of the reaction is associated with a low energy barrier separating the initial adduct from the product side ion-neutral complex.

Morgon, Nelson H.; Linnert, Harrald V.; de Souza, Luiz A. G.; Riveros, JoséM.

1997-09-01

302

SO2 emissions to the atmosphere from active volcanoes in Guatemala and El Salvador, 1999 2002  

NASA Astrophysics Data System (ADS)

Ground-based and aircraft correlation spectrometer (COSPEC) measurements at the principal active volcanoes in Guatemala (Pacaya, Santiaguito, Fuego, and Tacaná) and El Salvador (Santa Ana and San Miguel) were carried out at intervals during the period 1999 2002, as part of an attempt to measure baseline SO2 emissions of potentially dangerous volcanoes and to better understand their eruption mechanisms. We discuss some of the uncertainties involved in interpreting intermittent gas data, together with possible improvements. Other problems pertaining to current monitoring of SO2 and implications for future studies are also discussed. Santa Ana volcano is proposed to be a venting hydrothermal system, while Santiaguito, Fuego, Pacaya, and San Miguel all exhibit open-vent characteristics. Data for Tacaná volcano are presented, but are not enough to make descriptions of its characteristics and activity. Pacaya is emitting high fluxes of SO2 (>1000 tonnes/day), while the other vents are much lower emitters (20 300 tonnes/day in general). SO2 emissions at Pacaya suggest a large circulating and convecting high level chamber. The most recent emission rates at Fuego were measured during its current active phase (since January 2002). Average SO2 emission rates during 1999 2002 are: 1350 tonnes/day for Pacaya, 340 tonnes/day for Fuego, 120 tonnes/day for Santiaguito, 260 tonnes/day for San Miguel, 140 tonnes/day for Santa Ana, and 30 tonnes/day for Tacaná. These volcanoes account for about 6% to 12% of the estimated annual global volcanic output of SO2.

Rodríguez, Lizzette A.; Watson, I. Matthew; Rose, William I.; Branan, Yvonne K.; Bluth, Gregg J. S.; Chigna, Gustavo; Matías, Otoniel; Escobar, Demetrio; Carn, Simon A.; Fischer, Tobias P.

2004-12-01

303

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

304

Projections of SO2, NOx, NH3 and VOC Emissions in East Asia Up to 2030  

Microsoft Academic Search

Starting from an inventory of SO2, NOx, VOC and NH3 emissions for the years 1990 and 1995 in East Asia (Japan, South and North Korea, China, Mongolia and Taiwan), the temporal development of the emissions of the four air pollutants is projected to the year 2030 based on scenarios of economic development. The projections are prepared at a regional level

Z. Klimont; J. Cofala; W. Schöpp; M. Amann; D. G. Streets; Y. Ichikawa; S. Fujita

2001-01-01

305

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

EPA Science Inventory

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

306

SO2 Emission from Active Volcanoes Measured Simultaneously by COSPEC and mini-DOAS  

NASA Astrophysics Data System (ADS)

We measured SO2 emission rate from six volcanoes in Latin America (Santa Ana, El Salvador; San Cristóbal and Masaya, Nicaragua; Arenal and Poás, Costa Rica; Tungurahua and Sierra Negra, Ecuador) and from Mt. Etna, Italy, using two different remote sensing techniques: COSPEC (COrrelation SPECtrometer) and miniDOAS (miniaturized Differential Optical Absorption Spectroscopy). One of the goals of this study was to evaluate the differences in SO2 emission rates obtained by these two methods. The observed average SO2 emission rates measured during this study were 2688 t· d -1 from Tungurahua in July 2006, 2375 t· d -1 in September 2005 and 480 t· d -1 in February 2006 from Santa Ana, 1200 t· d -1 in May 2005 from Etna, 955 t· d -1 in March 2006 and 1165 t· d -1 in December 2006 from Masaya, 5400 t· d -1 of March 7, 2006 and 265 t· d -1 in March 2006 from San Cristobal, 113 t· d -1 in April 2006 from Arenal, 104 t· d -1 in April 2006 from Poás and 11 t· d -1 in July 2006 from Sierra Negra volcano. Most of the observed relative differences of SO2 emission measurements from COSPEC and miniDOAS were lower than 10%.

Barrancos, José; Roselló, José I.; Calvo, David; Padrón, Eleazar; Melián, Gladys; Hernández, Pedro A.; Pérez, Nemesio M.; Millán, Millán M.; Galle, Bo

2008-01-01

307

Sulfur Isotopes of SO2 and Aerosol sulphate during the onset of Arctic Winter  

NASA Astrophysics Data System (ADS)

Arctic haze is a commonly observed phenomenon especially in winter. The majority of Arctic haze is composed of sulphate from long range transport of pollutants from lower latitudes. Besides anthropogenic long range transport, atmospheric sulfur can also be released from biogenic material in the oceans. Sulfur isotopes can differentiate between anthropogenic and biogenic emissions and aids in the determination of the origin of sulfur. During the Fall of 2007, particulate sulphate and SO2 sulfur isotopes values were measured biweekly at Alert, Nunavut, Canada in part with the Canadian Surface Ocean - Lower Atmosphere study. High volume samplers collected aerosols on quartz filters and SO2 on treated cellulose acetate filters. An increase over an order of magnitude of SO2 concentrations in mid November was observed and most likely associated with Arctic haze and long range transport. ?34S values for SO2 and aerosol sulphate ranged between +4 and +11‰ throughout the sampling period. Comparison of sulfur concentrations and isotope signatures between the two species will be presented along with the temporal variations. Implications of offsets, differences and similarities of concentrations and isotope signatures will be discussed.

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

2010-12-01

308

Issues on orientifolds: on the brane construction of gauge theories with SO(2n) global symmetry  

Microsoft Academic Search

We discuss issues related to orientifolds and the brane realization for gauge theories with orthogonal and symplectic groups. We specifically discuss the case of theories with (hidden) global SO(2n) symmetry, from three to six dimensions. We analyze mirror symmetry for three dimensional N = 4 gauge theories, Brane Box Models and six-dimensional gauge theories. We also discuss the issue of

Amihay Hanany; Alberto Zaffaroni

1999-01-01

309

Cerebral regional oxygen saturation (crSO2): are different sensors comparable?  

PubMed

Background:? For measurement of cerebral regional oxygen saturation (crSO2) in neonates, one of the frequently used near-infrared spectroscopy devices is the INVOS 5100 with either the neonatal or pediatric sensor. Measurements between adult and pediatric sensors use different algorithms and differ by 10%. There are no published data comparing neonatal and pediatric sensors. Objective:? Aim of this study was to compare the neonatal sensor with the pediatric sensor of the INVOS 5100 device in a mixed cohort of neonates to recognize possible differences and enable interpretation of data. Methods:? In 40 neonates, crSO2 was measured in identical positions using both the neonatal and the pediatric sensor under identical conditions. Each sensor was reapplied five times to calculate mean values and standard deviations. Results:? Cerebral regional oxygen saturation measurements using the neonatal sensor (mean, 76.1?±?7.9) and crSO2 measurements using the pediatric sensor (mean, 76.4?±?8.1) were not different. Reproducibility was not significantly different with similar means of standard deviations (neonatal, 3.7?±?1.6; pediatric, 3.1?±?1.3). Conclusion:? In a mixed cohort of neonates, crSO2 measurements were identical when using the INVOS 5100 neonatal sensor and the pediatric sensor. We conclude that studies using the INVOS 5100 neonatal or pediatric sensor are well comparable. PMID:22686122

Morris, Nicholas; Pichler, Gerhard; Pocivalnik, Mirjam; Brandner, Anna; Müller, Wilhelm; Urlesberger, Berndt

2012-06-12

310

Fundamental Studies of Calcium-Based Sorbents for SO2 Control from Coal-Fired Boilers.  

National Technical Information Service (NTIS)

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

G. D. Silcox G. S. Samuelsen J. A. Cole J. C. Kramlich W. R. Seeker

1987-01-01

311

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

NASA Astrophysics Data System (ADS)

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

Smith, Kevin E.; Henrich, Victor E.

1985-10-01

312

FLYSPEC: A new Ultraviolet Correlation Spectrometer for the Detection of Volcanic SO2  

Microsoft Academic Search

A new miniature, lightweight and low cost ultraviolet Correlation Spectrometer, the FLYSPEC, has been developed as a replacement for the COSPEC, which has previously been the mainstay for the monitoring of volcanic SO2 emissions. The total mass of this battery operated prototype system, including computer\\/PDA, power, cabling, and GPS is less than 2 kg and can be mounted in a

K. Horton; G. Williams-Jones; H. Garbeil; A. J. Sutton; T. Elias

2002-01-01

313

DEPOSITION VELOCITIES OF SO2 AND O3 OVER AGRICULTURAL AND FOREST ECOSYSTEMS  

EPA Science Inventory

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

314

Absolute calibrations of SO2 and NO analyzers by photographic methods  

NASA Astrophysics Data System (ADS)

Two photometric methods using organic substances and solutions for calibrating flame photometer detectors (for measuring SO2) and chemiluminescent analyzers (for measuring NO) used in atmospheric chemistry are described. The accuracy of these methods (6%) depends on the applied measuring instruments, on the purity of the chemicals, and on the procedure applied in solution production.

Paffrath, M.

1984-11-01

315

Plasma Modification of Activated Carbon Fibers for Adsorption of SO2  

NASA Astrophysics Data System (ADS)

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

Che, Yao; Zhou, Jiayong; Wang, Zuwu

2013-10-01

316

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

EPA Science Inventory

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

317

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

EPA Science Inventory

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

318

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 3. SESSIONS 5B AND 6  

EPA Science Inventory

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

319

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 1. OPENING SESSION AND SESSIONS 1-3  

EPA Science Inventory

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

320

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

EPA Science Inventory

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

321

PROCEEDINGS: 1991 SO2 CONTROL SYMPOSIUM - VOLUME 2. SESSIONS 1-3  

EPA Science Inventory

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

322

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

EPA Science Inventory

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

323

Tuning Anion-Functionalized Ionic Liquids for Improved SO2 Capture.  

PubMed

You can have your cake and eat it too: A "dual-tuning" strategy for improving the capture of SO2 was developed by introducing electron-withdrawing sites on the anions to produce several kinds of functionalized ionic liquids. Those functionalized with a halogen group exhibited improved performance over their non-halogenated counterparts, leading to highly efficient and reversible capture. PMID:23939870

Cui, Guokai; Zheng, Junjie; Luo, Xiaoyan; Lin, Wenjun; Ding, Fang; Li, Haoran; Wang, Congmin

2013-08-12

324

SO2 uptake on ice spheres: Liquid nature of the ice-air interface  

Microsoft Academic Search

The amount of SO2 gas absorbed by ice of known surface area at equilibrium was used to estimate the volume of liquid water present at the ice-air interface at temperatures from -1 to -60°C. Calculations were based on Henry's law and acid dissociation equilibrium. The liquid volume is lowest at lower temperatures and ionic strength and under most conditions was

Martha H. Conklin; Roger C. Bales

1993-01-01

325

SO2 classification for air quality levels estimation using artificial intelligent techniques  

Microsoft Academic Search

This paper presents a new methodology to detect and classify SO2 concentration according to the air quality level. In this classification, meteorological variables are analyzed to make a classification decision. The method consists of three steps. In first step, we group using a SOM neural networks the pollutant concentration in two classes, these classes are noise data and validated data.

M. G. Cortina-Januchs; J. M. Barron-Adame; S. Ledesma; R. A. Matinez-Celorio; A. Vega-Corona

2006-01-01

326

Mobile IR and UV-Spectroscopic Measurements of CO, SO2 and VOC in Megacities  

Microsoft Academic Search

Three different types of optical instruments have been deployed at a field campaign in the Mexico City Metropolitan Area (MCMA) 2003 within three main applications: 1) Retrieval of total columns of CO at various positions within the MCMA. 2) Emission inventory of VOC (volatile organic compounds) and SO2 from a major industrial source in Tula 100km north of the MCMA.

J. Samuelsson; J. Mellqvist; B. Galle; B. de Foy; A. Garcia; L. T. Molina; M. J. Molina; R. Volkamer; E. Flores; M. Grutter

2004-01-01

327

Effect of Specific Surface Area on the Reactivity of CaO with SO2.  

National Technical Information Service (NTIS)

The paper discusses results of measuring the rate of reaction of calcined limestone (CaCO3) with sulfur dioxide (SO2) and oxygen (O2) at conditions that eliminate all resistances not associated with the lime (CaO) grain surface. Reactivity increased with ...

R. H. Borgwardt K. R. Bruce

1986-01-01

328

Simultaneous retrieval of volcanic ash and SO2 using MSG-SEVIRI measurements  

Microsoft Academic Search

Volcanic ash and sulphur dioxide masses from the November 2005 eruption of Karthala volcano, Comoros Islands, are simultaneously retrieved using rapid-scan, multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite. Retrievals are made every 15 min, which show that the ash and SO2 separate in the vertically sheared atmosphere producing

A. J. Prata; J. Kerkmann

2007-01-01

329

Radiative transfer retrievals for accurate UV-spectroscopic measurements of volcanic SO2 emissions  

Microsoft Academic Search

There is widespread use of passive remote sensing techniques to quantify trace gas column densities in volcanic plumes utilizing scattered sunlight as a light source. Examples include passive DOAS (ground-based or from satellite platforms), COSPEC, and the SO2 camera. In order to calculate trace gas concentrations or volcanic emission fluxes, knowledge about the optical path of the measured radiation through

C. Kern; T. Deutschmann; L. Vogel; M. Wöhrbach; T. Wagner; U. Platt

2009-01-01

330

UNIVERSITY OF WASHINGTON ELECTROSTATIC SCRUBBER TESTS: COMBINED PARTICULATE AND SO2 CONTROL  

EPA Science Inventory

The report gives results of tests of a 1700 a cu m/hr University of Washington electrostatic spray scrubber pilot plant on a coal-fired boiler to demonstrate its effectiveness for controlling fine particle and SO2 emissions. The multiple-pass portable pilot plant operates by comb...

331

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

Code of Federal Regulations, 2013 CFR

...of Performance for Stationary Combustion Turbines Emission Limits § 60.4330 What...sulfur dioxide (SO2 )? (a) If your turbine is located in a continental area, you...or (a)(3) of this section. If your turbine is located in Alaska, you do not...

2013-07-01

332

Reactivity Study of SO2 Control with Atmospheric and Pressure Hydrated Sorbents.  

National Technical Information Service (NTIS)

The report gives results of a study to develop an understanding of the factors that control the reactivity of hydrated sorbents toward SO2 in coal fired furnaces. It focused on the impacts of hydrate properties (e.g., particle size, surface area, and chem...

B. J. Overmoe J. M. McCarthy S. L. Chen W. R. Seeker D. W. Pershing

1986-01-01

333

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

EPA Science Inventory

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

334

ALTERNATIVES TO CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: CONCEPTUAL EVALUATION  

EPA Science Inventory

The report gives results of a conceptual engineering evaluation to screen supported metal oxides as alternatives to natural calcium-based sorbents (limestones and dolomites) for SO2 control in atmospheric and pressurized fluidized-bed combustion (FBC) processes. Alternative sorbe...

335

SO2 CONCENTRATION ESTIMATES FOR NEW YORK CITY, 1880-1980  

EPA Science Inventory

The purpose of this investigation was to estimate the yearly ambient concentration of SO2 and SO4 wet deposition from 1880 to 1980 for the greater New York City area. This information was used to reconstruct ambient concentrations at two New York Veterans Administration cemeterie...

336

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

EPA Science Inventory

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

337

SHELL NOX/SO2 FLUE GAS TREATMENT PROCESS: INDEPENDENT EVALUATION  

EPA Science Inventory

The report gives results of an independent evaluation of the Shell Flue Gas Treatment (SFGT) process which simultaneously reduces nitrogen oxide (NOx) and sulfur dioxide (SO2) emissions. NOx emissions from stationary sources may be reduced by 80-90 percent by applying selective c...

338

REGENERATION OF CALCIUM-BASED SO2 SORBENTS FOR FLUIDIZED-BED COMBUSTION: ENGINEERING EVALUATION  

EPA Science Inventory

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, operated with regeneration, ar...

339

THE EFFECT OF SO2 ON THE UPTAKE OF PARTICLES BY MOUSE BRONCHIAL EPITHELIUM  

EPA Science Inventory

In three experiments, the authors have explored the uptake and transport of collidal gold (Au) and iron oxide (Fe2O3) by normal and SO2-injured bronchial epithelium. In the first experiment mice were exposed to a 2-hr aerosol of Au; in the second experiment, mice were exposed to ...

340

QUALITY OF 'THOMPSON SEEDLESS' TABLE GRAPES FUMIGATED WITH CO2+SO2 AND METHYL BROMIDE.  

Technology Transfer Automated Retrieval System (TEKTRAN)

California table grapes must be fumigated with 6% CO2 plus 1% SO2 for 30 minutes for control of black widow spiders and with 40 g/m3 methyl bromide for 2 hours for control of other arthropod pests prior to shipment to Australian markets. The affect of this combination treatment on the quality of th...

341

WALL-FIRED BOILER DESIGN CRITERIA FOR DRY SORBENT SO2 CONTROL WITH LOW NOX BURNERS  

EPA Science Inventory

The report assesses the impact of Limestone Injection Multistage Burner (LIMB) technology on wall-fired utility boilers for both new and retrofit designs. Recent attention has focused on dry sorbent sulfur dioxide (SO2) control technology which, in conjunction with low-nitrogen-o...

342

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

Microsoft Academic Search

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

Limin Dong; Jiaxiang Yang

2002-01-01

343

The SO2 plume over the eastern US: Remote and in situ observations  

Microsoft Academic Search

Using information sensed from satellites to understand regional air quality problems shows great potential, but poses great challenges. The sources and distribution of SO2 over eastern North America may be areas where remote sensing can provide a powerful tool to improve our understanding. In the Eastern US, substantial amounts of high-sulfur coal are still burned without effective pollution controls. The

R. R. Dickerson; B. G. Doddridge; J. C. Hains; L. Marufu; J. P. Burrows; A. Richter

2003-01-01

344

HUMIDIFICATION OF FLUE GAS TO AUGMENT SO2 CAPTURE BY DRY SORBENTS  

EPA Science Inventory

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

345

MECHANISM OF SO2 AND H2SO4 AEROSOL ZINC CORROSION  

EPA Science Inventory

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

346

EFFECT OF SPECIFIC SURFACE AREA ON THE REACTIVITY OF CAO WITH SO2  

EPA Science Inventory

The paper discusses results of measuring the rate of reaction of calcined limestone (CaCO3) with sulfur dioxide (SO2) and oxygen (O2) at conditions that eliminate all resistances not associated with the lime (CaO) grain surface. Reactivity increased with the square of the Brunaue...

347

Optical characterization of UV multispectral imaging cameras for SO2 plume measurements  

NASA Astrophysics Data System (ADS)

Only a few years ago spectral imaging cameras for SO2 plume monitoring were developed for remote sensing of volcanic plumes. We describe the development from a first camera using a single filter in the absorption band of SO2 to more advanced systems using several filters and an integrated spectrometer. The first system was based on the Hamamatsu C8484 UV camera (1344 x 1024 pixels) with high quantum efficiency in the UV region from 280 nm onward. At the heart of the second UV camera system, EnviCam, is a cooled Alta U47 camera, equipped with two on-band (310 and 315 nm) and two off-band (325 and 330 nm) filters. The third system utilizes again the uncooled Hamamatsu camera for faster sampling (~10 Hz) and a four-position filter-wheel equipped with two 10 nm filters centered at 310 and 330 nm, a UV broadband view and a blackened plate for dark-current measurement. Both cameras have been tested with lenses with different focal lengths. A co-aligned spectrometer provides a ~0.3nm resolution spectrum within the field-of-view of the camera. We describe the ground-based imaging cameras systems developed and utilized at our Institute. Custom made cylindrical quartz calibration cells with 50 mm diameter, to cover the entire field of view of the camera optics, are filled with various amounts of gaseous SO2 (typically between 100 and 1500 ppm•m). They are used for calibration and characterization of the cameras in the laboratory. We report about the procedures for monitoring and analyzing SO2 path-concentration and fluxes. This includes a comparison of the calibration in the atmosphere using the SO2 cells versus the SO2 retrieval from the integrated spectrometer. The first UV cameras have been used to monitor ship emissions (Ny-Ålesund, Svalbard and Genova, Italy). The second generation of cameras were first tested for industrial stack monitoring during a field campaign close to the Rovinari (Romania) power plant in September 2010, revealing very high SO2 emissions (> 1000 ppm•m). The second generation cameras are now used by students from several universities in Romania. The newest system has been tested for volcanic plume monitoring at Turrialba, Costa Rica in January, 2011, at Merapi volcani, Indonesia in February 2011, at Lascar volcano in Chile in July 2011 and at Etna/Stromboli (Italy) in November 2011. Retrievals from some of these campaigns will be presented.

Stebel, K.; Prata, F.; Dauge, F.; Durant, A.; Amigo, A.,

2012-04-01

348

UV-DOAS for determination of NOx to HNO3/NO3- and SO2 to H2SO4/SO42-transformation rates  

NASA Astrophysics Data System (ADS)

This research employs UV-DOAS to log ambient atmospheric measurements of criteria pollutants and to gather data specifically for determining transformation rates. Species of concern include oxides of nitrogen (NO + NO2 = NOx) and sulfur dioxide (SO2). Combustion sources such as coal fired power plants continuously emit NOx and SO2, which enter the atmosphere and become dispersed and transformed, resulting in the formation of HNO3/NO3- and H2SO4/SO4(2-. The goal of this research is to determine the transformation rates from power plant plumes for NOx to HNO3/NO3- and SO2 to H2SO4/SO4(2- in a coastal environment. Continuous emission rates are known and ambient primary pollutant concentrations are continuously monitored with UV-DOAS. Secondary pollutant concentration levels are estimated from integrated annular denuder system measurements. The results of this research will be used to estimate the impacts of the nitrogen emissions from local power plants on the atmospheric nutrient loading to Tampa Bay and to assess the validity of current SO2 to H2SO4/SO42- modeled transformation rates in the Tampa environment.

Kenty, Kerstin L.

2002-01-01

349

SO2 emissions from persistently active explosive volcanoes: can we estimate their contribution using satellite instruments?  

NASA Astrophysics Data System (ADS)

The scientific community has long since recognized the importance of sulfur dioxide (SO2) on climate change. The most universally accepted theory is that large amounts of SO2 injected into the atmosphere will react to form sulfate aerosols that reflect sunlight, thereby decreasing global temperature. This cooling effect has been observed after large eruptions throughout the geologic and historic records. The exact effect of SO2 on global climate though is still poorly understood. Estimates of global volcanic SO2 emissions rely primarily on two sets of data: ground-based measurements of SO2 fluxes using COSPEC or DOAS and more recently satellite observations. Both of these usually represent ‘snapshots’ of the gas emissions and at only a few places is continuous monitoring and data acquisition possible. Because continuous data are so rare, many assumptions have to be made when trying to estimate the global volcanic SO2 input to the atmosphere. This is especially true when it comes to frequently exploding volcanoes. Most of their background activity is very low in intensity or the gas plume may simply not reach the stratosphere, both of which make it impossible for satellite instruments to detect it. On the other hand, while individual explosions produce plumes big enough to be detected by satellite instruments, they are often not captured from the ground because no continuous monitoring is in place. Therefore neither satellite nor ground-based data fully represents the total SO2 emissions of these volcanoes. We have analyzed satellite data for several persistently active explosive volcanic centers in an attempt to determine whether their SO2 emissions are detectable and to what extent we can quantify them. We used data from the Ozone Monitoring Instrument (OMI), which operates in the UV spectrum, the Moderate Resolution Imaging Spectroradiometer (MODIS) and, when available, the Advanced Spaceborne Thermal Emission Radiometer (ASTER), both of which operate in the thermal infrared spectrum. OMI and MODIS offer daily coverage of the Earth’s surface but preliminary results indicate that most of the SO2 emissions at persistently active explosive volcanoes (e.g. Semeru, Santiaguito, Sakurajima) are not detectable by these instruments, mostly due to their low spatial resolution. Only the strongest explosions produce plumes large enough to be detected by satellite instruments and even then, their signal is difficult to separate from ambient noise in the data. Some volcanoes that exhibit less frequent but more intense explosive activity (e.g. Soufrière Hills volcano) produce plumes that are clearly identifiable, but their background activity remains inconspicuous. ASTER’s higher spatial resolution theoretically provides a better means to detect small plumes. However its limited spectral resolution and more importantly, the 16-day return period, make it impossible to accurately quantify representative fluxes. Our study demonstrates the difficulty in estimating SO2 fluxes from persistently active explosive volcanoes from satellite data alone, and underlies the need for comprehensive and continuous ground-based measurements at this type of volcanoes.

Smekens, J.; Clarke, A. B.

2010-12-01

350

Solids Liquids and Gases  

NSDL National Science Digital Library

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

Salter, Ms.

2009-10-22

351

Health And Economic Impact Of Greenhouse Gas Emissions Reduction In Indonesia: SO2  

NASA Astrophysics Data System (ADS)

The objective of this study is to assess Indonesia's air quality. This comprised an assessment of Indonesia's air pollution levels and their impact on the development of health and the economics. Estimates are given of concentrations of one of the major pollutants: sulfur dioxide (SO2). Emissions are estimated for Indonesian region, based on energy consumption, derived from the MERGE simulation model. The air pollution levels projection for the year 2000 to the year 2100 are based on the IPCC scenarios, extended with some mitigation scenarios for the energy sector. If the Organisation for Economic Co-operation and Development (OECD) countries reduce their emissions, Indonesian oil consumption increases, and the emissions of SO2 are higher than in the baseline scenario. Health problems increase substantially, peaking to the middle of century in the A1B and B1 scenarios, and rising to the end of century in the A2 and B2 scenarios, while the health problem costs will be the highest during the middle of century in the A1B and B1 scenarios and toward the end of century in the A2 and B2 scenarios. With international trade in emission permits, Indonesia would be higher than in the baseline scenario, since more and more oil and coal using in domestic sources of energy, followed by higher of health problem cases and higher of health problem costs. The total cases of health problem are higher 18.5% than in the baseline scenario. If all countries reduce their emission, including Indonesia, the total concentrations of SO2 are lower than previous scenarios. The cases of health problem associated with SO2 are lower than in the baseline scenario and follow by the lower of the health problem costs. The costs of health problem associated with SO2 are to 35% lower than in the baseline scenario during the simulation period.

Susandi, A.

2004-12-01

352

Stomatal response of swordfern to volcanogenic CO2 and SO2 from Kilauea volcano  

NASA Astrophysics Data System (ADS)

The experimentally determined relationship between atmospheric pCO2 and plant stomata has been used to interpret large but transient changes in atmospheric composition, such as may have resulted from the eruptions of flood basalt. However, this relationship has not been tested in the field, i.e. in the vicinity of active volcanoes, to examine the specific effects of volcanogenic emissions. Moreover, the interpretation of paleoatmospheric pCO2 from fossil stomatal data assumes that the stomatal response resulted solely from variation in pCO2 and ignores the potential effect of outgassed SO2. We hypothesize that volcanogenic SO2 also has a significant effect on leaf stomata and test this hypothesis by measuring the stomatal index of the common swordfern (Nephrolepis exaltata) in the plumes of the actively outgassing vents of Kilauea volcano. We find that, compared to control locations, stomatal index is lowest at sample sites in the plume of Halema'uma'u Crater, where concentrations of both CO2 and SO2 are much higher than background. However, sites located directly in the plume of Pu'u O'o, where SO2 levels are high, but CO2 levels are not, also yield low values of stomatal index. We propose that shifts in the stomatal index of fossil leaves may record transient atmospheric increases in both SO2 and CO2, such as may be caused by eruptions of flood basalts. Calculations of pCO2 based on stomatal frequency are likely to be exaggerated.

Tanner, Lawrence H.; Smith, David L.; Allan, Amanda

2007-08-01

353

First estimate of volcanic SO2 budget for Vanuatu island arc  

NASA Astrophysics Data System (ADS)

The spatial and temporal coverage of measurements of volcanic gas emissions remains patchy. However, over the last decade, emissions inventories have improved thanks to new measurements of some of the lesser-known volcanic areas. We report on one such region—the Vanuatu island arc, in the Southwest Pacific—for which we now have sufficient systematic observations to offer a systematic emissions inventory. Our new estimate is based on SO2 flux measurements made in the period 2004-2009 with ultraviolet spectroscopy techniques for the following volcanoes: Yasur, Lopevi, Ambrym, Ambae, Gaua and Vanua Lava (from south to north). These are the first ever measurements for Lopevi, Gaua and Vanua Lava. The results reveal the Vanuatu arc as one of Earth's prominent sources of volcanic degassing with a characteristic annual emission to the atmosphere of ~ 3 Tg of SO2 (representing about 20% of hitherto published global estimates). Our new dataset highlights the sustained prodigious degassing of Ambrym volcano, whose 5 Gg day- 1 mean flux of SO2 represents nearly two-thirds of the total budget for the Vanuatu arc. This confirms Ambrym as one of the largest volcanic sources worldwide comparable to Etna, often considered as the most vigorous source of volcanic emission on Earth. We also report a high degassing for Ambae of ~ 2 Gg day- 1 SO2, representing more than 28% of the Vanuatu arc budget. Thus, 90% of the SO2 output from Vanuatu is focused in the central part of the arc (from Ambrym and Ambae) where magmas originate from enriched Indian-type mantle and where peculiar tectonic conditions could favor high magma production rates.

Bani, Philipson; Oppenheimer, Clive; Allard, Patrick; Shinohara, Hiroshi; Tsanev, Vitchko; Carn, Simon; Lardy, Michel; Garaebiti, Esline

2012-01-01

354

Retrieval of large volcanic SO2 columns from the Aura Ozone Monitoring Instrument: Comparison and limitations  

NASA Astrophysics Data System (ADS)

To improve global measurements of atmospheric sulfur dioxide (SO2), we have developed a new technique, called the linear fit (LF) algorithm, which uses the radiance measurements from the Ozone Monitoring Instrument (OMI) at a few discrete ultraviolet wavelengths to derive SO2, ozone, and effective reflectivity simultaneously. We have also developed a sliding median residual correction method for removing both the along- and cross-track biases from the retrieval results. The achieved internal consistencies among the LF-retrieved geophysical parameters clearly demonstrate the success of this technique. Comparison with the results from the Band Residual Difference technique has also illustrated the drastic improvements of this new technique at high SO2 loading conditions. We have constructed an error equation and derived the averaging kernel to characterize the LF retrieval and understand its limitations. Detailed error analysis has focused on the impacts of the SO2 column amounts and their vertical distributions on the retrieval results. The LF algorithm is robust and fast; therefore it is suitable for near real-time application in aviation hazards and volcanic eruption warnings. Very large SO2 loadings (>100 DU) require an off-line iterative solution of the LF equations to reduce the retrieval errors. Both the LF and sliding median techniques are very general so that they can be applied to measurements from other backscattered ultraviolet instruments, including the series of Total Ozone Mapping Spectrometer (TOMS) missions, thereby offering the capability to update the TOMS long-term record to maintain consistency with its OMI extension.

Yang, Kai; Krotkov, Nickolay A.; Krueger, Arlin J.; Carn, Simon A.; Bhartia, Pawan K.; Levelt, Pieternel F.

2007-12-01

355

A laboratory study of the effect of NO 2 on the atmospheric corrosion of zinc  

NASA Astrophysics Data System (ADS)

Studies on the effect of NO x on zinc corrosion are scarce and their results are variable and at times seemingly contradictory. This paper reports laboratory tests involving the dry deposition on zinc surfaces of 800 ?g m -3 NO 2, alone and in combination with 800 ?g m -3 SO 2, at temperatures of 35 and 25 °C and relative humidities of 90% and 70%. From the gravimetric results obtained and from the characterisation of the corrosion products by optical microscopy, scanning electron microscopy (SEM/EDX), grazing incidence X-ray diffraction (GIXD) and X-ray photoelectron spectroscopy (XPS), it has been verified that the corrosive action of NO 2 alone is negligible compared with SO 2. However, an accelerating effect has been observed when NO 2 acts in conjunction with SO 2 at 25 °C and 90% RH. At 35 °C and 90% RH, the accelerating effect is smaller, and at low relative humidities (70%), the synergistic effect is only slight, which suggests it may be favoured by the presence of moisture. In those cases where an accelerating effect has been observed, a greater proportion of sulphate ions has been found in the corrosion products, and nitrogen compounds have not been detected, indicating that NO 2 participates indirectly as a catalyst of the oxidation of SO 2 to sulphate.

Castaño, J. G.; de la Fuente, D.; Morcillo, M.

356

COMPRESSED MEDICAL GASES GUIDELINE  

Center for Biologics Evaluation and Research (CBER)

... COMPRESSED MEDICAL GASES GUIDELINE. (REVISED) FEBRUARY 1989. ... COMPRESSED MEDICAL GASES GUIDELINE. INTRODUCTION. ... More results from www.fda.gov/drugs/guidancecomplianceregulatoryinformation/guidances

357

Atmospheric inversion of SO2 and primary aerosol emissions for the year 2010  

NASA Astrophysics Data System (ADS)

Natural and anthropogenic emissions of primary aerosols and sulphur dioxide (SO2) are estimated for the year 2010 by assimilating daily total and fine mode aerosol optical depth (AOD) at 550 nm from the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite instrument into a global aerosol model of intermediate complexity. The system adjusts monthly emission fluxes over a set of predefined regions tiling the globe. The resulting aerosol emissions improve the model performance, as measured from usual skill scores, both against the assimilated observations and a set of independent ground-based measurements. The estimated emission fluxes are 67 Tg S yr-1 for SO2, 12 Tg yr-1 for black carbon (BC), 87 Tg yr-1 for particulate organic matter (POM), 17 Pg yr-1 for sea salt (SS, estimated at 80% relative humidity) and 1206 Tg yr-1 for desert dust (DD). They represent a difference of +53%, +73%, +72%, +1% and -8%, respectively, with respect to the first guess (FG) values. Constant errors throughout the regions and the year were assigned to the a priori emissions. The analysis errors are reduced for all species and throughout the year, they vary between 3% and 17% for SO2, 1% and 130% for biomass burning, 25% and 89% for fossil fuel, 1% and 200% for DD and 1% and 5% for SS. The maximum errors on the global-annual scale for the estimated fluxes (considering temporal error dependence) are 12% for SO2, 39% for BC, 41% for POM, 43% for DD and 40% for SS. These values represent a decrease as compared to the global-annual errors from the FG of 12% for SO2, 42% for BC, 47% for POM, 50% for DD and 95% for SS. The largest error reduction, both monthly and yearly, is observed for SS and the smallest one for SO2. The sensitivity and robustness of the inversion system to the choice of the first guess emission inventory is investigated by using different combinations of inventories for industrial, fossil fuel and biomass burning sources. The initial difference in the emissions between the various setups is reduced after the inversion. Furthermore, at the global scale, the inversion is sensitive to the choice of the BB inventory and not so much to the industrial and fossil fuel inventory. At the regional scale, however, the choice of the industrial and fossil fuel inventory can make a difference. The estimated baseline emission fluxes for SO2, BC and POM are within the estimated uncertainties of the four experiments. The resulting emissions were compared against projected emissions for the year 2010 for SO2, BC and POM. The new estimate present larger emissions than the projections for all three species, with larger differences for SO2 than POM and BC. These projected emissions are in general outside the uncertainties of the estimated emission inventories.

Huneeus, N.; Boucher, O.; Chevallier, F.

2013-03-01

358

Radiative transfer retrievals for accurate UV-spectroscopic measurements of volcanic SO2 emissions  

NASA Astrophysics Data System (ADS)

There is widespread use of passive remote sensing techniques to quantify trace gas column densities in volcanic plumes utilizing scattered sunlight as a light source. Examples include passive DOAS (ground-based or from satellite platforms), COSPEC, and the SO2 camera. In order to calculate trace gas concentrations or volcanic emission fluxes, knowledge about the optical path of the measured radiation through the plume is necessary. For ground-based measurements, a straight photon path through the plume has been assumed in the past although it was known that this is not always true. Satellite retrievals apply a variety of techniques to estimate the air mass factor (AMF) for a particular measurement. Recently, model studies were conducted to quantify the effects of realistic radiative transfer in and around volcanic plumes on ground-based remote sensing measurements of SO2. These have shown that possible errors span more than an order of magnitude, and that both, over and underestimation of the true column density can occur. Actual errors depend on parameters such as distance between instrument and plume, plume SO2 concentration and aerosol load, as well as aerosol conditions in the ambient atmosphere. Here, we focus on retrieving radiative transfer parameters directly from UV-spectroscopic measurements of SO2 between 300 and 325 nm. Data analysis techniques are discussed that allow the retrieval of SO2 vertical column density and aerosol extinction coefficient inside the volcanic plume. A three-dimensional backward Monte Carlo radiative transfer model is used to simulate the measurement results that would be obtained for a certain physical state of the atmosphere and volcanic plume. Thus, a solution to the forward problem is obtained. By varying the state vector until the simulations match the remote sensing observations, this problem can be inverted. Sample ground-based measurements and retrievals are presented to demonstrate the power of the new techniques for satellite validation (ground truth) as well as to show the necessity of applying such corrections, even under seemingly ‘ideal’ measurement conditions. The discussed retrievals could greatly improve the accuracy of UV-spectroscopic satellite measurements of SO2 in volcanic plumes.

Kern, C.; Deutschmann, T.; Vogel, L.; Wöhrbach, M.; Wagner, T.; Platt, U.

2009-12-01

359

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...  

Code of Federal Regulations, 2010 CFR

...bypass, and multiple stacks for SO2 emissions and heat input determinations...bypass, and multiple stacks for SO2 emissions and heat input determinations...monitoring system in the common stack and combine emissions for the affected units...

2010-07-01

360

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...  

Code of Federal Regulations, 2010 CFR

...bypass, and multiple stacks for SO2 emissions and heat input determinations...bypass, and multiple stacks for SO2 emissions and heat input determinations...monitoring system in the common stack and combine emissions for the affected units...

2009-07-01

361

Competitive Adsorption Study of CO2 and SO2 on CoII3[CoIII(CN)6]2 Using DRIFTS  

SciTech Connect

Diffuse reflectance infrared Fourier transform spectroscopy was used to study the competitive adsorption of CO2 and SO2 on the cobalt Prussian blue analogue CoII3[CoIII(CN)6]2 at 298 K. Characteristic peaks for adsorbed CO2 and SO2 species were identified and their relative areas, measured simultaneously as a function of pressure at 298 K, varied in accordance with a Langmuir-Freundlich isotherm fitted to both gases in the low-coverage Henry’s Law limit. Evidence for co-adsorption of trace water was also obtained, as well as the apparent formation of an analogous cobalt nitroprusside compound as a reaction product under certain conditions. The several aspects of the adsorption of CO2 and SO2 on CoCo determined in this work point to an important role for real-time diffuse reflectance infrared measurements in adsorption studies, particularly in the case of competitive adsorption where the occurrence and fate of molecular-level markers arising from more than one adsorbed species can be monitored simultaneously. Depending on the application, this may more than offset certain quantitative limitations of the technique that confine measurements to a relatively narrow set of experimental conditions and demand careful consideration of the effects of sample preparation and treatment.

Windisch, Charles F.; Thallapally, Praveen K.; McGrail, B. Peter

2010-09-15

362

Modelling of the long-range transport of volcanic SO2 and ash plumes utilising space-based measurements for early warning purposes  

NASA Astrophysics Data System (ADS)

Volcanic eruptions and unrest are among the main natural hazards, which influence nature, human beings and climate and are a hazard to aircraft. Most of the active volcanoes are not monitored regularly yet. The combination of satellite observations and atmospheric transport modelling can provide global information on the emission, dispersion and transport of ash and trace gases. One of these trace gases is sulphur dioxide (SO2 ), which is a good indicator for volcanic unrest and activity. Within the project Exupéry which is a part of the Geotechnology Program a fast response system for volcanic unrest is developed. The program is funded by the German Federal Ministry of Education and Research (BMBF). In case of volcanic unrest a network of relevant instruments (seismicity, ground deformation and gas emissions) can be installed directly at the volcano. In addition to ground-based information space-based data are collected that can be directly forwarded to decision makers and observatories. SO2 total columns are retrieved from GOME-2 on MetOp satellite in near-real time and with a global coverage in about one day. By means of a backward trajectory ensemble matching technique relevant parameters such as the location of the emission source, the moment of the eruption as well as the emission height are estimated. Using these parameters as a first guess of the source term, the Lagrangian particle dispersion model FLEXPART is initialised. The long-range transport of volcanic SO2 for several days can then be modelled. The results have been compared to space-based observations from IASI (Infrared Atmospheric Sounding Interferometer) and AIRS (Atmospheric Infrared Sounder), as well as to ground-based measurements. Furthermore a comparison between the Lagrangian particle dispersion model results and the results of an Eulerian chemical transport model (POLYPHEMUS) using the same source term is shown. SO2 is often used as a marker for volcanic ash dispersion for early warning purposes, because the satellite-based observation of ash particles is complicated and ambiguous. For an investi-gation of this approach the results of a comparison between modelled SO2 transport and ash observations from MODIS and IASI are shown for recent eruptions, such as the eruption of Kasatochi volcano in Alaska in August 2008. The retrieval of a first ash indicator from IASI is based on a principle component analysis (PCA). For the derivation of the ash cloud out of MODIS the Brightness Temperature Differences (BTD) between 11m and 12m bands are used.

Maerker, Cordelia; Erbertseder, Thilo; Klueser, Lars; Rix, Meike; Valks, Pieter

363

Ship-borne MAX-DOAS measurements of NO2 and BrO in the marine boundary layer  

NASA Astrophysics Data System (ADS)

With this poster studies on tropospheric background abundances of NO_2 and BrO in the marine boundary layer of the Atlantic Ocean covering a latitude range of about 88^o shall be presented. For that purpose, a measurement device of the Multi-Axial Differential Optical Absorption Spectroscopy (MAX-DOAS) was employed that could record scattered light spectra from several viewing directions simultaneously and two-dimensionally in the ultraviolet (UV) wavelength region. The measurements were conducted in November 2001 on board of the research vessel POLARSTERN on a journey from Bremerhaven, Germany, to Cape Town, South Africa. In order to gain significant results from the UV data the resolution of the spectra with different viewing directions, imaged on a two-dimensional CCD camera, had to be adjusted. In this contribution the two evaluation methods tested, the so-called cross convolution and cross evaluation (the latter comprising special convolution routines), and the respective results will be referred to. The analysis, including elaborate Radiative Transfer Modelling (RTM), resulted in a maximum of the daily averages of the NO_2 mixing ratio in the marine boundary layer on 10 November 2001 at about 48^oN 5^oW in the Channel between France and England of (360±130)ppt, which coincided with the BrO minimum of (1.3±0.6)ppt. The respective NO_2 minimum, again coinciding with a local BrO maximum, was found on 20 November 2001 at about 6^oN 16^oW in the middle Atlantic with (60±12)ppt for NO_2 and (2.8±0.5)ppt for BrO respectively. The results for the other days will be presented on this poster as well as a comparison to earlier ship measurements of NO_2 abundance at sunrise and sunset for each day of the passage. As the main objective of this research project is to provide data sets in order to control and calibrate the DOAS device SCIAMACHY mounted on the European research satellite ENVISAT the studies have been continued in 2003 and are planned to be extended into the future. With continuous optimisation of the experimental set-up it will be possible to expand the range of trace gases to other weak atmospheric absorbers of interest like HCHO, SO2, IO or OClO.

Bossmeyer, J.; von Friedeburg, C.; Friess, U.; Heck, A.; Wagner, T.; Platt, U.

2003-04-01

364

Oxidation State of Volcanic Gases and the Interior of Io  

Microsoft Academic Search

We used thermochemical equilibrium calculations to constrain the oxygen fugacity (fO2) of volcanic gases on Io. Three types of calculations were done: (1) Upper limits for fO2 from Voyager IRIS upper limits for the SO3\\/SO2 ratio and the O3 abundance in the Loki volcanic plume; (2) lower limits for fO2 from the observed SO\\/SO2 ratio in Io's atmosphere; (3) oxygen

Mikhail Yu. Zolotov; Bruce Fegley

1999-01-01

365

Quantification of the gas mass emitted during single explosions on Stromboli with the SO 2 imaging camera  

Microsoft Academic Search

We performed measurements using an SO2 imaging camera of the SO2 gas mass emitted during five discrete explosive events on Stromboli volcano on 3 October 2006. The SO2 gas mass released during discrete explosions was 15–40kg per explosion, producing 3–8% of the total daily SO2 gas emission, demonstrating that in terms of gas flux Strombolian explosions are a second-order phenomenon

Toshiya Mori; Mike Burton

2009-01-01

366

Simultaneous reduction of NO x and SO 2 emissions from coal combustion by calcium magnesium acetate  

Microsoft Academic Search

The potential of calcium magnesium acetate (CMA) as a medium for the simultaneous control of NOx and SOx emissions has been investigated using a pulverized coal combustion rig operating at 80kW. A US and a UK coal of significantly different sulphur contents were used as primary fuel and CMA was injected in solution form into the combustion gases by horizontally

W. Nimmo; A. A. Patsias; E. Hampartsoumian; B. M. Gibbs; P. T. Williams

2004-01-01

367

Lifetime assessment analysis of Galileo Li/SO2 cells: Final report  

SciTech Connect

Galileo Li/SO2 cells from five lots and five storage temperatures were studied to establish a database from which the performance of flight modules may be predicted. Nondestructive tests consisting of complex impedance analysis and a 15-s pulse were performed on all cells. Chemical analysis was performed on one cell from each lot/storage group, and the remaining cells were discharged at Galileo mission loads. An additional number of cells were placed on high-temperature accelerated aging storage for 6 months and then discharged. All data were statistically analyzed. Results indicate that the present Galileo design Li/SO2 cell will satisfy electrical requirements for a 10-year mission. 10 figs., 4 tabs.

Levy, S.C.; Jaeger, C.D.; Bouchard, D.A.

1988-12-01

368

Absolute rate coefficient and mechanism of gas phase reaction of ketenyl radical and SO2.  

PubMed

The kinetics of the gas phase reaction of the ketenyl radical with SO(2) was investigated over the temperature range 296-568 K using a laser-photofragment/laser-induced fluorescence technique (LP/LIF). The reactor pressure was 10 Torr N(2) or He. Pulsed photolysis of ketene (CH(2)CO) at 193 nm was used as the source of HCCO radicals. The rate coefficient for the title reaction was determined to be described by k(T) = (1.05 ± 0.33) × 10(-12) exp[(690 ± 98)K/T] cm(3) s(-1) molecule(-1) (2? error). We applied the coupled cluster and density functional theory to explore the mechanism of the title reaction. The dominant reaction pathway begins with a barrierless association of the C of the CH group of HCCO and the O atom of SO(2). PMID:23020066

Du, Lin; Carl, Shaun A

2012-10-10

369

SO2-rock interaction on Io - Reaction under highly oxidizing conditions  

NASA Astrophysics Data System (ADS)

Laboratory simulations are used here to test the possibility that interactions of SO2 and silicates can produce Na-S compounds which can account for the observed surface enrichment of Na relative to Si on Io. It is concluded that there are three viable hypotheses for the nature and origin of the Na compounds on the surface of Io: (1) Na2SO4 from SO2-silicate interactions, (2) Na-sulfides from elemental S, silicate interactions, and (3) directly erupted volcanic Na. The present studies indicate the elemental Si is not required to form Na compounds in crustal igneous interactions. Thus, the presence of Na compounds provides no constraint on elemental S but igneous formation of Na-S compounds is not tied to models of Io which contain elemental S.

Johnson, M. L.; Burnett, D. S.

1993-01-01

370

Rotation-vibration interactions in highly excited states of SO2 and H2CO  

NASA Astrophysics Data System (ADS)

Canonical Van Vleck perturbation theory (CVPT) is used to investigate rotation-vibration mixing of highly excited vibrational states of SO2 and H2CO. For SO2, a nearly complete separation of the rotational and vibrational degrees of freedom is found, even for J = 12 and E(vib) = 11,000/cm. In contrast, for H2CO, extensive mixing is observed between rotational and vibrational degrees of freedom at similar rotational excitation but with E(vib) = 8000/cm. Although a-axis Coriolis coupling is pronounced, b- and c-axis Coriolis couplings play an important additional role in mixing states with different Ka quantum numbers. The implementation of CVPT, the choice of internal coordinates, and the convergence of the results are discussed in detail.

McCoy, Anne B.; Burleigh, Darin C.; Sibert, Edwin L., III

1991-11-01

371

Differential SO2 column measurements of the Mt. Pinatubo volcanic plume  

NASA Astrophysics Data System (ADS)

Differential SO2 column measurements of the Mt. Pinatubo volcanic plume were made from a NASA Electra aircraft flying in the Caribbean in July, 1991. The mean column content of the volcanic plume in the Caribbean was 25 micro-atm m (2.5 Dobson units) with periods of over 100 micro-atm m observed. The data indicate that an aerosol absorption or scattering effect occurs for long slant paths (low sun-elevation angles) and that 41 micro-atm m (an average obtained for 1-2 airmasses) is more representative of a true column average. Dispersion of the initial cloud from Mt. Pinatubo and a one-month SO2-to-sulfate conversion-time constant are in good agreement with the column contents found here.

Hoff, Raymond M.

1992-01-01

372

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

Code of Federal Regulations, 2010 CFR

...procedures for SO2, NOX, Hg, and flow rate. 75.33 Section 75.33 ...procedures for SO2 , NOX , Hg, and flow rate. (a) Following initial certification...the required SO2 , NOX , and flow rate monitoring system(s) at a...

2009-07-01

373

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

Code of Federal Regulations, 2010 CFR

...procedures for SO2, NOX, Hg, and flow rate. 75.33 Section 75.33 ...procedures for SO2 , NOX , Hg, and flow rate. (a) Following initial certification...the required SO2 , NOX , and flow rate monitoring system(s) at a...

2010-07-01

374

A new type of corona discharge reactor for simultaneous removal of NO and SO2 from flue gas  

Microsoft Academic Search

An experimental study on the simultaneous removal of NO and SO2 in a simulated flue gas has been carried out using multipoint to water corona discharge reactor. In a simulate flue gas containing of 400 ppm NO and 400 ppm SO2, the NO and SO2 can be simultaneous removal. The gas phase NO is oxidized by corona discharge and converted

Dong Li-Min; Lu Wei; Chi Xiao-Chun; Yang Jia-Yang

2004-01-01

375

CIMS measurements of HNO 3 and SO 2 at the South Pole during ISCAT 2000  

Microsoft Academic Search

HNO3 and SO2 were measured by chemical ionization mass spectrometry at the South Pole (SP) during ISCAT 2000 (December, 2000). HNO3 mixing ratios averaged 22pptv and ranged from less than 5 to 68pptv. A simple steady state photochemical analysis indicates that most of the time HNO3 is deposited to the snow with a lifetime of the order of a few

L. G. Huey; D. J. Tanner; D. L. Slusher; J. E. Dibb; R. Arimoto; G. Chen; D. Davis; M. P. Buhr; J. B. Nowak; R. l. Mauldin III; F. L. Eisele; E. Kosciuch

2004-01-01

376

Atmospheric environmental capacity of SO 2 in winter over Lanzhou in China: A case study  

Microsoft Academic Search

The total emission control method based on atmospheric environmental capacity is the most effective in air pollution mitigation.\\u000a The atmospheric environmental capacities of SO2 on representative days over Lanzhou are estimated using the numerical models RAMS, HYPACT and a linear programming model,\\u000a according to the national ambient air quality standard of China (NAAQSCHN). The results show that the fields of

Xingqin An; Hongchao Zuo; Lijuan Chen

2007-01-01

377

Health risk analysis of volcanic SO 2 hazard on Vulcano Island (Italy)  

Microsoft Academic Search

Since the last eruption of the Fossa crater in 1888–1890, intense volcanic degassing has been remaining on Vulcano Island\\u000a of Sicily (Italy). Toxic sulfur dioxide (SO2) of the solfataric action in this area represents, when inhaled, a permanent natural hazard harming humans. Approximately\\u000a 500 permanent residents live and 15,000 tourists visit during the summer time the Porto village in the

Christian D. Klose

2007-01-01

378

Hydration products of FBC wastes as SO 2 sorbents: comparison between ettringite and calcium hydroxide  

Microsoft Academic Search

Fluidized bed combustion (FBC) enables the in situ capture of SO2, but generates large amounts of wastes whose composition and physico-chemical properties make both landfilling and reuse in traditional fields of application (e.g., cement and concrete industries) problematic. Reactivation by water hydration of the desulphurizing ability of these residues is considered a viable mean for their recycling: besides Ca(OH)2, this

Fabio Montagnaro; Marianna Nobili; Piero Salatino; Antonio Telesca; Gian Lorenzo Valenti

2008-01-01

379

Interactions during fermentation between pesticides and oenological yeasts producing H2S and SO2  

Microsoft Academic Search

The degradative action of two strains of Saccharomyces cerevisiae, producers of large quantities of H2S and SO2, on eight sulphur-containing insecticides (chlorpyrifos-methyl, dimethoate, fenitrothion, fenthion, malation, methidation, parathion, and quinalphos) was studied. Moreover, the influence of these compounds on the fermentative activity of the yeasts was investigated. The yeasts adsorbed and degraded the studied insecticides to various extents, but their

P. Cabras; V. L. Garau; A. Angioni; G. A. Farris; M. Budroni; L. Spanedda

1995-01-01

380

Calcium magnesium acetate and urea advanced reburning for NO control with simultaneous SO 2 reduction  

Microsoft Academic Search

Calcium magnesium acetate (CMA) shows potential as a reductant for simultaneous NOx and SOx removal from coal-fired combustion plant. The performance of urea co-injection with CMA on NO reduction in an ‘advanced reburn’ (AR) configuration has been investigated with a view to optimization of the process in a pulverized coal-fired furnace operating at 80kW. The impact on SO2 reduction has

W Nimmo; A. A Patsias; E Hampartsoumian; B. M Gibbs; M Fairweather; P. T Williams

2004-01-01

381

Mapping SO 2 Frost on Io by the Modeling of NIMS Hyperspectral Images  

Microsoft Academic Search

We analyze a collection of hyperspectral images of Io acquired by the near infrared mapping spectrometer (NIMS) of Galileo during the G2 to E16 orbits of Jupiter. This analysis leads to the geographical distribution and physical characterization of SO2 frost deposits over about three-fourths of Io's surface. These deposits are excellent tracers of various phenomena, including volcanic production and emission,

Sylvain Douté; Bernard Schmitt; Rosaly Lopes-Gautier; Robert Carlson; Laurence Soderblom; James Shirley

2001-01-01

382

Simultaneous SO 2 and NO removal using sorbents derived from rice husks: An optimisation study  

Microsoft Academic Search

In this study, rice husk-derived ash (RHA) was hydrated with CaO and then impregnated with copper to synthesize a sorbent that was subsequently tested for its capacity in simultaneous removal of SO2 and NO from a simulated flue gas. The effect of various sorbent preparation parameters, including copper loading, RHA\\/CaO ratio, hydration period and NaOH concentration, on the desulphurisation\\/denitrification capacity

L. C. Lau; K. T. Lee; A. R. Mohamed

2011-01-01

383

The sensitivity to SO 2 of the SAW gas sensor with triethanolamine modified with boric acid  

Microsoft Academic Search

The sensitivity to SO2 of the SAW gas sensor coated with triethanolamine (TEA) modified with boric acid (H3BO3) (TEA and H3BO3 were mixed with a mole ratio 3:1) has been investigated. A better stability of the modified TEA film compared with that of TEA film was observed. Both the steady response ?f and the transient response (?f\\/?t)max varied linearly with

Shuji Qin; Zhongjie Wu; Zhongyue Tang; Yilin Song; Fanzhong Zeng; Dong Zhao

2000-01-01

384

A Rapid Air Titration Method for Determining SO2 Concentration in Inhalation Chambers  

Microsoft Academic Search

A rapid air titration method for determining SO2 concentration in inhalation chambers has been validated using the pararosaniline-formaldehyde (PRA) method of West and Gaeke. This air-titration (iodate) method is an adaptation of iodometric methods using a starch indicator. Potassium iodate and an excess of potassium iodide are used in the reaction. Sampling is completed in ten minutes or less and

EILEEN A. SNYDER; E. D. PALMES

1985-01-01

385

Remote CO, COS, CO2, SO2, HCl detection and temperature estimation of volcanic gas  

Microsoft Academic Search

Volcanic gas from an inaccessible fumarole at Aso volcano, Japan, was recently measured with a Fourier Transform InfraRed (FT-IR) spectral radiometer. Absorption features of CO, COS, CO2, SO2, and HCl were identified in the volcanic plume spectra. This is the first time the five volcanic gas components are detected simultaneously by a remote technique. Based on the measured CO\\/CO2 ratio

Toshiya Mori; Kenji Notsu

1997-01-01

386

Characterization of NOx, SO2, ethene, and propene from industrial emission sources in Houston, Texas  

Microsoft Academic Search

The Houston-Galveston-Brazoria urban area contains industrial petrochemical sources that emit volatile organic compounds and nitrogen oxides, resulting in rapid and efficient ozone production downwind. During September to October 2006, the NOAA WP-3D aircraft conducted research flights as part of the second Texas Air Quality Study (TexAQS II). We use measurements of NOx, SO2, and speciated hydrocarbons from industrial sources in

R. A. Washenfelder; G. J. Frost; T. B. Ryerson; E. L. Atlas; J. A. de Gouw; F. M. Flocke; A. Fried; J. S. Holloway; D. D. Parrish; J. Peischl; D. Richter; S. M. Schauffler; J. G. Walega; C. Warneke; P. Weibring; W. Zheng

2010-01-01

387

Sigma phase formation in alloys for SO2/SO3 thermal energy storage systems  

NASA Astrophysics Data System (ADS)

A screening test was completed which identifies the tendency for sigma phase formation in alloys for SO2/SO3 thermal energy storage systems. The candidate alloys include austenitic and ferritic stainless steels, Fe-Ni Base, and Ni base alloys. Test specimens were aged for 4,000 hours at ambient temperature, 700, 800, 900, and 1000 C. Aged specimens were tested for Charpy V-notch toughness. Decreases in toughness upon aging correlated well with the observed changes in microstructure.

Hughes, D. A.

1980-02-01

388

Combustion and SO 2?NO x emissions of bituminous coal particles treated with calcium magnesium acetate  

Microsoft Academic Search

Experiments were conducted in an externally heated drop-tube furnace to assess the effectiveness of the chemical calcium magnesium acetate [CMA, CaMg2(CH3COO)6] as a combustion catalyst and a coal pretreatment agent for reducing SO2 emissions. Bituminous coal particles of two distinct sizes, pulverized (75–90 ?m) or micronized and beneficiated (mean diameter ?3.5 ?m) were burned. To measure the coal particle temperatures

Ajay Atal; Judi Steciak; Yiannis A. Levendis

1995-01-01

389

Regulation as the Mother of Innovation: The Case of SO2 Control  

Microsoft Academic Search

This paper explores the relationship between government actions and innovation in an environmental control technology—sulfur dioxide (SO2) control technologies for power plants—through the use of complementary research methods. Its findings include the importance of regulation and the anticipation of regulation in stimulating invention; the greater role of regulation, as opposed to public R&D expenditures, in inducing invention; the importance of

MARGARET R. TAYLOR; EDWARD S. RUBIN; DAVID A. HOUNSHELL

2005-01-01

390

ABSORPTION OF NO AND SO2 IN FE(II)EDTA SOLUTIONS II. PACKED COLUMN SIMULATION  

Microsoft Academic Search

Two methods were applied in simulating the height of a packed column required for the removal of NO and SO2 by absorption into Fe(II)-EDTA solutions. The first method used a double-stirred cell to simulate a packed column by matching the gas- and liquid-phase mass transfer coefficients of the two device. The second method used the differential mass balance including reaction

SIU-MING YIH; CHYI-WOEI LII

1988-01-01

391

O(P-3(J)) alignment from the photodissociation of SO2 at 193 nm  

Microsoft Academic Search

The 193-nm photodissociation Of SO2 has been studied using the resonantly enhanced multiphoton ionization of ground-state O(P-3(J)), coupled with velocity-map ion imaging. The dependence of the ion images on the linear polarization of pump and probe radiation has been used to determine the electronic angular momentum alignment of the recoiling, state-selected atoms, together with their speed distribution and translational anisotropy.

M. Brouard; D. R. Cireasa; A. P. Clark; T. J. Preston; C. Vallance; G. C. Groenenboom; O. S. Vasyutinskii

2004-01-01

392

Cross sections for electron scattering from sulfuryl chloride fluoride (SO2ClF) molecules  

NASA Astrophysics Data System (ADS)

Absolute total cross section (TCS) for electron scattering from sulfuryl chloride fluoride (SO2ClF) molecules was measured in a linear transmission experiment at energies ranging from 0.6 to 370 eV. The experimental TCS energy function has a deep minimum (30 × 10-20 m2) at 3 eV which separates two distinct TCS enhancements. Below 3 eV the TCS curve increases steeply towards lower energies with a small resonant maximum visible near 2.2 eV. Above 3 eV the TCS is dominated by second pronounced enhancement with the maximum (45 × 10-20 m2) peaked near 9.5 eV. The experimental TCS findings are—at intermediate energies—satisfactorily reproduced with our total cross section estimation based on calculations of integral elastic (in independent atom approximation) and ionization (binary-encounter-Bethe approach) cross sections. The TCS measured for SO2ClF is also compared with experimental TCSs for molecules containing sulfur as a central atom and it is found that some features observed for SO2ClF are shared by others of the compared molecules.

Szmytkowski, Czeslaw; Mozejko, Pawel; Kwitnewski, Stanislaw; Ptasinska-Denga, Elzbieta; Domaracka, Alicja

2005-08-01

393

Optical Emission Detection of SO2 by Microfabricated Inductively Coupled Plasma (mICP).  

NASA Astrophysics Data System (ADS)

In this work a microfabricated ICP is used to optically detect trace amounts of SO_2. An mICP system consists of a planar microfabricated plasma source and miniature aluminum chamber and operates at 1-10 torr pressure and 0.7-3.5 W of 493 MHz RF power. An SO2 fraction as low as 2 ppm was measured using the intensity of atomic sulfur emission at 469.5 nm. The detection limit, however, depends on power and pressure, and is as low as 190 ppb. As power increases from 1 W to 3.5 W, the detection limit improves from 400 ppb to 190 ppb due to the increase in electron density. Improvement of detection limits from 300 ppb to 190 ppb was achieved by increasing the pressure from 2.5 to 5.6 torr. In addition, this miniature ICP has the ability to excite the entire SO2 molecule, which is a desirable feature as compared to large-scale plasma spectrometry systems, where triatomic molecules generally get destroyed due to extensive dissociation in the plasma. Therefore, unlike large-scale ICP-OES, which is traditionally used for atomic detection, this mICP-OES is also a promising molecular detection tool.

Minayeva, Olga; Hopwood, Jeffrey

2001-10-01

394

Volcanic SO2 flux time series from MSG-SEVIRI satellite measurements.  

NASA Astrophysics Data System (ADS)

Quantitative retrieval maps of SO2 and ash columnar abundances retrieved from thermal infrared (TIR) satellite images of volcanic plumes can be converted into flux time series if the wind field is known. In a recently published work we showed how to reconstruct SO2 and ash fluxes from a single TIR MODIS image instrument aboard TERRA and AQUA polar satellites. The results obtained were then successfully compared with the SO2 flux measured with the FLAME ground-based network of DOAS instruments in a case study of the December, 2006 Mt. Etna (Sicily, Italy) eruption. The key point of this work was that a single multispectral image framing a volcanic cloud can be regarded as the evolution in time of physical and volcanological parameters, and effectively records many hours of volcanic activity. We highlight that the flux reconstruction obtained from satellite data with this technique offers new perspectives that are particularly valuable for the monitoring of remote volcanoes and allows some insights on the volcanic processes driving the eruptions. Here we show how this promising approach can be easily extended to a collection of TIR MSG-SEVIRI images exploiting the high acquisition frequency achieved by an instrument on board on a geostationary platform.

Merucci, L.; Corradini, S.

2012-04-01

395

Non-Mass Dependent Fractionation of Sulfur and Oxygen Isotopes During SO2 UV Photolysis  

NASA Astrophysics Data System (ADS)

We are investigating the fractionation of sulfur and oxygen isotopes (?33S, ?34S, ?36S, ?17O and ?18O) caused by photodissociation of gaseous SO2. Mutual shielding of SO2 during photodissociation may be a possible mechanism for anomalous sulfur isotope fractionation that occurred in the Earth's early atmosphere. These experiments consist of two cylindrical Pyrex gas cells, placed end to end, with fused silica end windows. We should see primary isotope effects in the gas cell closest to the UV source, as Farquhar et al. did in their experiments by using a single gas cell (Farquhar et al., 2001). Using two gas cells enables us to see the different isotopic compositions that arise from mutual shielding. The gas cells are filled with commercial SO2 at pressures of 0.02-0.10 atm, comparable to molecular cloud and volcanic emission column densities, and then irradiated for 2-7 days with a deuterium lamp. The use of a broadband source (180-400 nm), in contrast to line sources, during isotopic photodissociation gives a closer analog to solar UV radiation. The residual gaseous SO2 is collected and converted to SF6 and O2 via reduction of SO2 to Ni3S2 and NiO and subsequent fluorination. I will be presenting ?33S, ?34S, ?36S, ?17O and ?18O data from the photolysis experiments. Sulfur isotope results are qualitatively similar to calculated trends by Lyons (2007), based on a model of mutual shielding, with the slope of the ?33S/?34S graph being slightly greater than the mass-dependent slope, and the slope of the ?36S/?34S graph slightly less than the mass-dependent slope. However, the slope of our ?36S/?33S line is closer to the natural Archean sample slope of -0.9 (Farquhar et al., 2000) than it is to -3 found by Lyons. NMD effects are also evident for the oxygen isotopes.

Pen, A.; Clayton, R. N.

2008-12-01

396

Nyiragongo and Nyamulagira volcanoes SO2-rich plume: a human health impact on North Kivu population?  

NASA Astrophysics Data System (ADS)

Located in the east of the Democratic Republic of Congo (DRC), Nyiragongo and Nyamulagira volcanoes are among the most active of the continent. Nyiragongo (last eruption in January 2002) hosts a sub-permanent lava lake that produces a SO2-rich plume. Its neighbor Nyamulagira makes major contributions to these emissions during its frequent eruptive periods (~2-3 years; last occurred in November 2011). An evaluation of the permanent volcanic plume impact on the population health has not been undertaken to date. It is the objective of this study conducted at two different scales. - 1999-2010 data were extracted from the Health Information System (HIS). Through temporal and spatial analyses (Poisson regression), acute respiratory infection (ARI) cases routinely registered in health centres located under the plume were studied. No strong relationship of the ARI cases number was identified neither with distance to volcanoes, nor with eruptive months. ARI were also statistically compared (cross correlation) to SO2 concentrations (ground level) measured by using Multi-Axis Differential Optical Absorption Spectroscopic (MAX-DOAS) sensors located around Nyiragongo volcano. Correlation between ARI cases number and SO2 concentration values appears to be statistically positive and significant. These last results encouraged us to both study more deeply the health data collected during the 2011 Nyamulagira eruption and to undertake a large scale study. - Following the last Nyamulagira eruption, a field survey was conducted in March 2012. The objective was to collect general population's specific health information. At the same time, passive SO2 filters were distributed throughout the surveyed area. Statistical analyses highlight new correlations between respiratory infection criteria and SO2 ground concentrations. Other impacts, linked either to health or to agriculture, can also be underlined through our results, as well as through field observations. This on-going study aims at determining the magnitude and geographical extent of the impact of volcanic plumes on the population health. This should contributes to define the appropriate sanitation recommendations and lead to effective volcanic impact reduction on human health.

Michellier, Caroline; Dramaix, Michèle; Wilondja, Jeanpy; Yalire, Matthieu; Bosco Kahindo, Jean; Kervyn, François

2013-04-01

397

Mechanisms of pulmonary NO2 absorption.  

PubMed

Although NO2-induced cytotoxic responses have been well characterized, the specific mechanisms responsible for initiating toxicity remain equivocal. The inhomogeneous distribution of epithelial injury suggests that differential interactions between NO2 and the lung surfaces may contribute to the extent of regional responses. Consequently, we have initiated studies to characterize the mechanisms which govern NO2 absorption and the initiation of the toxic cascade. Due to limitations in whole animal models, we have utilized numerous in vitro exposure models. Herein we examine our recent investigations. In brief synopsis: NO2 uptake is governed by reaction between inhaled NO2 and constituents of the pulmonary surface lining layer (SLL). The predominant reaction pathway involves hydrogen abstraction producing HNO2 and an organic radical. NO2 uptake is first-order with respect to NO2 ([NO2] < 10 ppm), is aqueous substrate-dependent, and is saturable. Conditions at the gas/liquid interface proper modulate the rate of transfer into the aqueous phase. Most likely, NO2 does not diffuse unreacted through the SLL. Absorption is proportional to inspired dose. The clearance efficiency may be modulated by ventilation frequency and the effective surface area of the exposed air space surfaces. We propose that the profile and concentration of SLL constituents mediate both the dosimetry and the extent of epithelial responses. Due to differential lining layer conditions, the relationship between absorbed dose and response may be complex and may exhibit anatomic and host variability. PMID:8023330

Postlethwait, E M; Bidani, A

1994-05-20

398

Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes  

NASA Astrophysics Data System (ADS)

Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ±40 mrad (2.3°) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 1012 molecules cm-3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds.

Vogel, L.; Galle, B.; Kern, C.; Delgado Granados, H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lübcke, P.; Alvarez Nieves, J. M.; Cárdenas Gonzáles, L.; Platt, U.

2011-09-01

399

Early in-flight detection of SO2 via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes  

NASA Astrophysics Data System (ADS)

Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ± 40 mrad (2.3°) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 1012 molecules cm-3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds.

Vogel, L.; Galle, B.; Kern, C.; Delgado Granados, H.; Conde, V.; Norman, P.; Arellano, S.; Landgren, O.; Lübcke, P.; Alvarez Nieves, J. M.; Cárdenas Gonzáles, L.; Platt, U.

2011-05-01

400

Measurements of trace gas distributions using Long-path DOAS-Tomography during the motorway campaign BAB II: experimental setup and results for NO 2  

NASA Astrophysics Data System (ADS)

The Tomographic Differential Optical Absorption Spectroscopy (Tom-DOAS) technique and results from a first application are presented. This novel technique serves to measure 2-3-dimensional concentration fields of different trace gases (e.g. NO 2, SO 2, ozone) in the planetary boundary layer on a small scale (100-10 000 m) by the use of multiple light paths. Ways to use telescopes, lamps, retroreflector arrays and spectrometers for the simultaneous measurement of many light-paths are proposed. The results from a first Long-path Tom-DOAS experiment next to a German motorway, which was part of the BAB II campaign April/May 2001 [Edition of the Institut für Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe/Universität Karlsruhe, pp. 45, 2001), are presented. From the measurements along 16 different light paths vertical profiles on both sides of the motorway as well as a two-dimensional map of the NO 2 vehicle emission plume are derived. The concentration distributions agree qualitatively with model simulations of an earlier campaign.

Pundt, I.; Mettendorf, K.-U.; Laepple, T.; Knab, V.; Xie, P.; Lösch, J.; Friedeburg, C. v.; Platt, U.; Wagner, T.

401

Vibrational spectra of an LiNO3-(CH3)2SO2 system  

NASA Astrophysics Data System (ADS)

Raman and IR absorption spectra were studied and molecular relaxation characteristics of vibrations of the anion and solvent were calculated for an xLiNO3-(1 - x)(CH3)2SO2 system ( x = 0.1, 0.2, 0.3, 0.4 M). It was found that it is impossible to increase the concentration of free ions involved in charge transfer in such a system by either increasing the temperature or changing the concentration composition in the studied range of x.

Gafurov, M. M.; Rabadanov, K. Sh.; Ataev, M. B.; Aliev, A. R.; Ahmedov, I. R.; Kakagasanov, M. G.; Kraminin, S. P.

2012-05-01

402

Comparison of Low Cost Miniature Spectrometers for Volcanic SO2 Emission Measurements  

PubMed Central

Miniature ultraviolet USB coupled spectrometers have become ubiquitously applied over the last decade for making volcanic SO2 emission rate measurements. The dominantly applied unit has recently been discontinued however, raising the question of which currently available devices should now be implemented. In this paper, we consider, and make recommendations on this matter, by studying a number of inexpensive compact spectrometers in respect of measurement performance and thermal behaviour. Of the studied units, the Avaspec demonstrated the best prospects for the highest time resolution applications, but in the majority of cases, we anticipate users likely preferring the less bulky USB2000+s.

Kantzas, Euripides P.; McGonigle, Andrew J. S.; Bryant, Robert G.

2009-01-01

403

Sulfur isotope fractionation during heterogeneous oxidation of SO2 on mineral dust  

NASA Astrophysics Data System (ADS)

Mineral dust is a major fraction of global atmospheric aerosol, and the oxidation of SO2 on mineral dust has implications for cloud formation, climate and the sulfur cycle. Stable sulfur isotopes can be used to understand the different oxidation processes occurring on mineral dust. This study presents measurements of the 34S/32S fractionation factor ?34 for oxidation of SO2 on mineral dust surfaces and in the aqueous phase in mineral dust leachate. Sahara dust, which accounts for ~60% of global dust emissions and loading, was used for the experiments. The fractionation factor for aqueous oxidation in dust leachate is ?leachate = 0.9917±0.0046, which is in agreement with previous measurements of aqueous SO2 oxidation by iron solutions. This fractionation factor is representative of a radical chain reaction oxidation pathway initiated by transition metal ions. Oxidation on the dust surface at subsaturated relative humidity (RH) had an overall fractionation factor of ?het = 1.0096±0.0036 and was found to be almost an order of magnitude faster when the dust was simultaneously exposed to ozone, light and RH of ~40%. However, the presence of ozone, light and humidity did not influence isotope fractionation during oxidation on dust surfaces at subsaturated relative humidity. All the investigated reactions showed mass-dependent fractionation of 33S relative to 34S. A positive matrix factorization model was used to investigate surface oxidation on the different components of dust. Ilmenite, rutile and iron oxide were found to be the most reactive components, accounting for 85% of sulfate production with a fractionation factor of ?34 = 1.012±0.010. This overlaps within the analytical uncertainty with the fractionation of other major atmospheric oxidation pathways such as the oxidation of SO2 by H2O2 and O3 in the aqueous phase and OH in the gas phase. Clay minerals accounted for roughly 12% of the sulfate production, and oxidation on clay minerals resulted in a very distinct fractionation factor of ?34 = 1.085±0.013. The fractionation factors measured in this study will be particularly useful in combination with field and modelling studies to understand the role of surface oxidation on clay minerals and aqueous oxidation by mineral dust and its leachate in global and regional sulfur cycles.

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

2012-06-01

404

Sulfur isotope fractionation during heterogeneous oxidation of SO2 on mineral dust  

NASA Astrophysics Data System (ADS)

Mineral dust is a major fraction of global atmospheric aerosol, and the oxidation of SO2 on mineral dust has implications for cloud formation, climate and the sulfur cycle. Stable sulfur isotopes can be used to understand the different oxidation processes occurring on mineral dust. This study presents measurements of the 34S/32S fractionation factor ?34 for oxidation of SO2 on mineral dust surfaces and in the aqueous phase in mineral dust leachate. Sahara dust, which accounts for ~ 60% of global dust emissions and loading, was used for the experiments. The fractionation factor for aqueous oxidation in dust leachate is ?leachate = 0.9917 ± 0.0046, which is in agreement with previous measurements of aqueous SO2 oxidation by iron solutions. This fractionation factor is representative of a radical chain reaction oxidation pathway initiated by transition metal ions. Oxidation on the dust surface at subsaturated relative humidity (RH) had an overall fractionation factor of ?het = 1.0096 ± 0.0036 and was found to be almost an order of magnitude faster when the dust was simultaneously exposed to ozone, light and RH of ~ 40%. However, the presence of ozone, light and humidity did not influence isotope fractionation during oxidation on dust surfaces at subsaturated relative humidity. A positive matrix factorization model was used to investigate surface oxidation on the different components of dust. Ilmenite, rutile and iron oxide were found to be the most reactive components, accounting for 85% of sulfate production with a fractionation factor of ?34 = 1.012 ± 0.010. This overlaps within the analytical uncertainty with the fractionation of other major atmospheric oxidation pathways such as the oxidation of SO2 by H2O2 and O3 in the aqueous phase and OH in the gas phase. Clay minerals accounted for roughly 12% of the sulfate production, and oxidation on clay minerals resulted in a very distinct fractionation factor of ?34 = 1.085 ± 0.013. The fractionation factors measured in this study will be particularly useful in combination with field and modelling studies to understand the role of surface oxidation on clay minerals and aqueous oxidation by mineral dust and its leachate in global and regional sulfur cycles.

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

2012-01-01

405

Remote CO, COS, CO2, SO2, HCl detection and temperature estimation of volcanic gas  

NASA Astrophysics Data System (ADS)

Volcanic gas from an inaccessible fumarole at Aso volcano, Japan, was recently measured with a Fourier Transform InfraRed (FT-IR) spectral radiometer. Absorption features of CO, COS, CO2, SO2, and HCl were identified in the volcanic plume spectra. This is the first time the five volcanic gas components are detected simultaneously by a remote technique. Based on the measured CO/CO2 ratio of 2.6 × 10-3, the equilibrium temperature of the volcanic gas is estimated to be 750° ± 120°C.

Mori, Toshiya; Notsu, Kenji

1997-08-01

406

Error analysis of SO2 measurement by multiwavelength differential absorption lidar  

NASA Astrophysics Data System (ADS)

A multiwavelength method to improve the accuracy of a differential absorption lidar (DIAL) for measuring SO2 in the lower atmosphere is presented. A dual-DIAL method consisting of a combination of two DIAL pairs (three or four measurement wavelengths) is proposed, and the measurement error is estimated from the lidar equation. By the selection of appropriate measurement wavelengths, the effects of ozone and aerosols can be suppressed. In principle, the accuracy can be improved to below 1 ppb for 300-m range resolution.

Fukuchi, Tetsuo; Goto, Naohiko; Fujii, Takashi; Nemoto, Koshichi

1999-01-01

407

BPS states in type IIB SUGRA with SO(4) × SO(2)gauged symmetry  

NASA Astrophysics Data System (ADS)

We present an extension of our construction (hep-th/0606199) exhibiting SO(4) × SO(2) symmetry. We extend the previously presented ansatz by introducing a U(1) gauge field. The presence of the gauge field allows for more general values of the Killing spinor U(1) charge. One more time we identify a four dimensional Kahler structure and a Monge-Ampere type of equation parametrized by the U(1) Killing spinor charge. In addition we identify 2 scalars that parametrize the supersymmetric solutions, one of which is the Kahler potential.

Donos, Aristomenis

2007-05-01

408

Wigner--Eckart Theorem and the Group SO(2,1)  

NASA Astrophysics Data System (ADS)

We deal here with the use of the Wigner-Eckart theorem to calculate the matrix elements of a hyperbolic vector operator \\overrightarrowV belonging to a pseudo-Euclidean space generated by the pseudo-orthogonal group SO(2,1). We particularly focus on calculating the matrix elements of this vector operator within the basis of the hyperbolic angular momentum \\overrightarrowT; the components hatT_1, hatT_2, hatT3 of the \\overrightarrowT used in this work satisfy an SO(2,1) Lie algebra whose Casimir operator is given by \\overrightarrow T^2=hatT_3^2-hatT_1^2- hatT_2^2. We show that the commutation rules between the components of \\overrightarrowV and \\overrightarrowT can be inferred from the algebra of ordinary angular momentum. We then show that, by analogy to the Wigner-Eckart theorem of ordinary angular momentum, we can calculate the matrix elements of \\overrightarrowV within a representation where \\overrightarrow T^2 and hatT3 are both diagonal. One of us (NZ) acknowldges the support of Jacksonville State University for this work through a university research grant.

Zettili, Nouredine; Boukahil, Abdelkrim

2002-04-01

409

Investigating Errors in Static COSPEC Measurements of Volcanic SO2 Plumes  

NASA Astrophysics Data System (ADS)

Correlation spectrometer (COSPEC) measurements of sulfur dioxide (SO2) from active volcanoes are collected using both airborne and ground-based methods. Utilizing both methods for volcano monitoring is useful because a more robust data set is produced, comparisons can be made between the different techniques, and environmental conditions or logistics can inhibit the use of either method. However, a number of errors are unique to the static method that make fixed-position measurements less reliable than airborne measurements. Among these are increased path lengths, variable plume geometries, and inconsistent background conditions. We use COSPEC measurements collected at Soufriere Hills Volcano, Montserrat to investigate shortfalls in static COSPEC measurements. The data consist of five scans collected from a fixed position in February 2001 in which a clinometer was used to measure scan rotational speed. Data collected at Soufriere Hills are ideal because 1) helicopter and static measurements are both collected on a near-daily basis, and 2) static measurements are consistently lower than airborne measurements. Plume geometry and viewing angle are investigated as causes of underestimation of static SO2 measurements. Constraining errors associated with fixed-position scanning makes static COSPEC measurements more accurate and dependable, especially important when conditions prohibit airborne surveys.

Shannon, J. M.; Watson, I. M.; Bluth, G. J.; Carn, S.

2001-12-01

410

The influence of CO2-SO2 - brine mixtures on petrophysical parameters of potential reservoir sandstones  

NASA Astrophysics Data System (ADS)

The main objective of this study is to investigate the interaction between CO2-CO2-SO2 - brine mixtures and sandstone samples from potential CO2 reservoir formations (Buntsandstein, Stuttgart Formation) on petrophysical parameters under realistic pressure and temperature conditions. This is essential to assess the required purity of the CO2 from the capture process in order to avoid reservoir damage. We built a long-term experimental flow assembly designed for a maximum pressure of 600 bar at a maximum working temperature of 150°C. The internal set-ups allow for the determination of P and S wave velocities, electrical conductivity and permeability at samples of 30mm in diameter and 60mm in length. Additionally, the experimental equipment is capable for capillary pressure experiments. In this case, elastic wave velocities and electrical resistivity are determined as functions of the water saturation of the rock samples. To date, we have performed long-term (several weeks) two-phase flow experiments using CO2 and brine at different ratios. The flow experiments showed not the expected changes of the measured physical rock properties. This can be explained by the high residual water saturation of most samples, which vary between 40 and 70%. We also present first results from experiments with CO2-SO2- mixtures.

Kummerow, Juliane; Spangenberg, Erik; Giese, Ronny

2010-05-01

411

Comprehensive COSPEC measurements to measure SO2 conversions in moist tropical atmosphere, Santa Ana, El Salvador  

NASA Astrophysics Data System (ADS)

Santa Ana is an andesitic stratovolcano (summit 2381 m) in western El Salvador which has not erupted magma since 1920. Santa Ana's summit crater lake temperature and gas emission rates increased between May and September 2000 prompting further investigation. On February 8 and 9 2001, SO2 emission rates were measured using a COSPEC instrument at a) Cerro Verde (2030 m elevation), as stationary position observing the plume ca. 2 km from the vent and b) from a vehicle traveling in the Santa Ana-Sonsonate highway (some 5-8 km from the vent). The resulting fluxes were 3.657 kg s-1 (316 t d-1) and 2.476 kg s-1 (214 t d-1) respectively. Using a wind speed of 7.5 m s-1 these results yield a range of loss rates from 5 x 10-4 to 1 x 10-3 s-1, similar to plumes of similar altitude (1-3 km) observed at Etna and Montserrat. We will further constrain this loss rate by analysing other data taken at a variety of azimuthal angles (effective distances from the plume) taken on February 8. We will also use the overall experience to plan a field survey for Santa Ana which can focus on quantifying SO2 conversion rates, to take advantage of the unusually good geometry there for ground-based COSPEC measurements.

Branan, Y.; Rose, W. I.; Matias, O.; Escobar, D.; Bluth, G.; Watson, I. M.; Shannon, J.

2001-12-01

412

Simultaneous SO2 and ash retrievals using the volcanic plume removal (VPR) procedure  

NASA Astrophysics Data System (ADS)

A novel procedure for the simultaneous retrieval of SO2 and ash abundances in a volcanic plume from MODIS thermal infrared (TIR) images is presented. The proposed procedure is simple, extremely fast and requires as inputs only the plume altitude and temperature. Here it is described and applied on two Mt. Etna (Italy) test case eruptions, but can be easily extended and applied to any volcano. The core of the volcanic plume removal (VPR) procedure is the calculation of the background radiance obtained by linear interpolation of the radiance measured in the area surrounding the plume. In this way the absorption effect of the volcanic plume can be removed from the image: the VPR procedure computes the radiances that would have been measured by the sensor if the plume was missing and reconstructs a new image without the plume. The difference of the new image and the original data highlights the plume area and allows the computation of the plume transmittance in three TIR-MODIS bands: 29, 31 and 32 (8.6, 11.0 and 12.0 ?m). The procedure works very well when the surface under the plume is uniform, as it is often the case with plume widths of few tens of kilometers. As a consequence, it has no problems when the plume is above the sea, but still produces fairly good results in more challenging and not easily modeled conditions, such as images with land or uniform cloud layers under the plume. The plume transmittances are derived in two steps: (1) using a simple model with the plume at a fixed altitude and neglecting the layer of atmosphere above it; (2) refining the first result with polynomial relationships adapted for the geographical region. MODIS bands 31 and 32 are SO2 transparent and, from their transmittances, the ash particle effective radius (Re) and the aerosol optical depth at 550 nm (AOD550) are computed. A simple relation between the ash transmittances of bands 31 and 29 is demonstrated for the typical ash of Etna and used for the SO2 columnar content estimation. The parameters of the polynomial relationship have been derived from more than 200 thousands MODTRAN simulations performed to describe the Etna plumes and local situations. The comparison of the VPR procedure results with these more than 200 thousands different cases shows a frequency distribution of the differences saying that: the Re error is less than ±0.5 ?m in more than 60% of the cases; the AOD550 error is less than ±0.125 in 80% of the cases; the SO2 error is less than ±0.5 gm-2 in more than 60% of the considered cases. The VPR procedure has been applied in two case studies of recent eruptions occurred at Mt. Etna volcano and successfully compared with the results obtained with the established SO2 and ash retrievals based on the look-up tables (LUTs) method (Corradini et al., 2009). By re-computing the parameters of the polynomial relationships, the VPR procedure can be applied to different volcanoes as well as extended to other sensors and ash types.

Merucci, Luca; Corradini, Stefano; Pugnaghi, Sergio; Guerrieri, Lorenzo; Arvani, Barbara

2013-04-01

413

Impact of national NOx and SO2 control policies on particulate matter pollution in China  

NASA Astrophysics Data System (ADS)

China's air pollution control policies during the 12th Five Year Plan (2011–2015) are characterized by the targets of 10% nitrogen oxides (NOx) reduction and 8% sulfur dioxide (SO2) reduction from the 2010 levels. In this study, the Community Multi-scale Air Quality (CMAQ) modeling system was used to evaluate the impact of only SO2, only NOx, and joint SO2/NOx control measures on particulate matter pollution, the greatest concern for urban air quality in China. Four emission scenarios were developed for 2015, including a business-as-usual scenario, a reference NOx control scenario based on the governmental plan, an accelerated NOx control technology scenario, and a scenario assuming joint controls of NOx and SO2 based on the governmental plan. Under the planned NOx control measures, the annual mean concentrations of particulate matter less than or equal to 2.5 ?m (PM2.5) decline by 1.5–6 ?g m?3, i.e. 1.6%–8.5%, in the majority of eastern China. The largest reduction occurs in the middle reach of the Yangtze River. Under accelerated NOx control measures, the annual average PM2.5 concentration reductions (compared with the business-as-usual scenario) in eastern China are 65% higher than the reductions under planned control measures. The unusual increase of PM2.5 concentrations in the North China Plain and the Yangtze River Delta during January after the reductions of NOx emissions was an integrated effect of excessive NOx, the ammonia-rich inorganic aerosol chemistry, and the non-methane volatile organic compounds (NMVOC) sensitive photochemical regime. Under the joint controls of NOx and SO2, the annual mean PM2.5 concentrations decline over 3 ?g m?3, i.e. 3.2%–13%, in the majority of eastern China, and some areas in the middle reach of the Yangtze River have reductions as large as 6–8.3 ?g m?3, i.e. 5.0%–13%. The average PM2.5 concentration reductions in eastern China are 1.20 ?g m?3, 3.14 ?g m?3, 3.57 ?g m?3, 4.22 ?g m?3 in January, May, August, and November, respectively. The corresponding declining rates are 2.3%, 12.2%, 14.3%, and 8.1%, respectively. More stringent policies should be implemented in winter to reduce the heavy pollution periods. The annual average PM2.5 concentration reductions in three major city clusters are comparable with the average reductions of eastern China. Stringent regional control policies are required for the significant improvement of particulate air quality in major city clusters.

Zhao, Bin; Wang, Shuxiao; Wang, Jiandong; Fu, Joshua S.; Liu, Tonghao; Xu, Jiayu; Fu, Xiao; Hao, Jiming

2013-10-01

414

Quantification of the Gas Mass Emitted During a Single Explosion on Stromboli with the SO2 Camera  

NASA Astrophysics Data System (ADS)

The recent development of the SO2 camera is a powerful new tool for volcanologists that allows quantitative imaging of SO2 amounts within volcanic plumes. Such SO2 images are information-rich compared to traditional measurements by COSPEC or compact UV spectrometer systems which measure the equivalent of one pixel in an SO2 image. Furthermore, using time-series of SO2 images, we can examine short- lived events on the order of seconds and quantitatively constrain wind speed, the greatest source of error in flux determination. The new capabilities offered by the SO2 camera herald a major step forward for understanding degassing processes and therefore civil defence. On October 3 and 4, 2006, we performed SO2 imaging measurements at Stromboli volcano, Italy. The SO2 camera was placed on the north-eastern flank of the volcano about 2.4 km from the summit craters and recorded SO2 images with a time-interval of 5.0 seconds on Oct. 3 and 3.2 seconds on Oct. 4, respectively. More than 1500 SO2 plume images were collected. Major variations in SO2 flux were observed over a timescale of a few minutes and several peaks were seen. By relating the major increases of the flux with a movie of the SO2 plume images, we can conclude that the main cause of these variations was strombolian explosions. In the afternoon of Oct. 3, we took the SO2 camera to the summit of the volcano. The aim of the measurements was to quantify the amount of SO2 emitted during a single explosion. The SO2 camera was set up 400 m north of the craters and a single UV band-pass filter (Center wavelength: 310 nm, HWHM 10 nm) was used in the measurements. We obtained more than 600 plume images with time interval between frames of ~2 seconds. By analyzing the SO2 images, we could separate several explosive events from the background quiescent degassing. The amount of SO2 emitted by a single explosion was 15 - 40 kg which corresponds to approximate total gas mass of 350 - 900 kg. Assuming that the gas slug originated from ~75 MPa (as demonstrated by recent FTIR measurements on Stromboli) we may calculate the volume of the slug at that pressure. Using the ideal gas law and assuming a spherical bubble in the conduit, at a pressure of 75 MPa and temperature of 1150°, this gas amount will occupy a sphere with radius 0.8 - 1.1 m.

Mori, T.; Burton, M.; Wright, T. E.

2007-12-01

415

The solubility of SO2 and the dissociation of H2SO3 in NaCl solutions  

Microsoft Academic Search

Measurements of the solubility of SO2 and the dissociation of SO2 + H2O in NaCl solutions at ionic strengths from 0.1 to 6 m and temperatures of 5 and 25 C are presented. The measurements are used to determine the Pitzer (1979) parameters for the interaction of Na(+) with SO2, HSO3(-), SO3(2-). The stoichiometric dissociation constants, pK1(asterisk) and pk2(asterisk) of

Frank J. Millero; J. Peter Hershey; George Johnson; Jia-Zhong Zhang

1989-01-01

416

Theoretical and experimental investigation of the C 2 H + SO 2 reaction over the range T = 295-800 K  

NASA Astrophysics Data System (ADS)

The rate constant of C 2 H + SO 2 over T = 295 to 800 K is k SO 2 ( T ) = (0.86 ± 0.08) T 3.80±0.13 exp[-(1222 ± 79)/ T ]. The rate constants are moderately high and show negative temperature dependence. C 2 H + SO 2 plays a significant role in combustion and interstellar environments, where its main products will be HCCO + SO.

Swinnen, Saartje; Elsamra, Rehab M. I.; Nguyen, Vinh Son; Peeters, Jozef; Carl, Shaun A.; Nguyen, Minh Tho

2011-09-01

417

A scaled quantum mechanical force field for the sulfuryl halides II. The SO(2)XF (X=Cl, Br) halides.  

PubMed

Force fields and vibrational wavenumbers were calculated for the molecules SO(2)XF (X=Cl, Br) using DFT techniques. The previously available experimental data and assignments for SO(2)ClF and SO(2)BrF were partially confirmed by the theoretical results. These data were subsequently used in the definition of scaled quantum mechanics force fields for such molecules. A comparison of the obtained force constants is made with results previously published for the SO(2)X(2) molecules. PMID:16257717

Fernández, L E; Varetti, E L

2005-11-01

418

Molecular interactions of SO2 with carbonate minerals under co-sequestration conditions: a combined experimental and theoretical study  

SciTech Connect

We present a combined experimental and theoretical study investigating the reactivity between selected and morphologically important surfaces of carbonate minerals with supercritical CO2 with co-existing H2O and SO2. Trace amounts of SO2 cause formation of CaSO3 in the form of hannebachite in the initial stages of SO2 adsorption and transformation. Atomistic simulations of these initial steps indicate a somewhat catalytic activity of water, which is enhanced by the presence of Magnesium atoms in the mineral surface. Under co-sequestration conditions, traces of water are not likely to cause carbonate dissolution, however the presence of SO2 greatly stabilizes the sulfite product.

Glezakou, Vassiliki Alexandra; McGrail, B. Peter; Schaef, Herbert T.

2012-09-01

419

Remote sensing atmospheric trace gases with infrared imaging spectroscopy  

NASA Astrophysics Data System (ADS)

Atmospheric pollution affects human health, food production, and ecosystem sustainability, causing environmental and climate change. Species of concern include nitrogen oxides, sulfur dioxide (SO2 ), and the greenhouse gases (GHG) methane (CH4 ) and carbon dioxide (CO2 ). Trace gas remote sensing can provide source detection, attribution, monitoring, hazard alerts, and air quality evaluation.

Leifer, Ira; Tratt, David M.; Realmuto, Vincent J.; Gerilowski, Konstantin; Burrows, John P.

2012-12-01