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1

Emission estimates of particulate matter (PM) and trace gases (SO2, NO and NO2) 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), SO2, NO and NO2 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 SO2, NO and NO2 from dung cake, fuel-wood and crop residue over this region are also determined (SO2: 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 NO2: 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, SO2, NO and NO2 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

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

NASA Astrophysics Data System (ADS)

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

Mallik, C.; Lal, S.

2012-12-01

3

Quantifying HCHO, NO2 and SO2 Emissions from Industrial Point Sources with Imaging DOAS  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

4

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

5

GROWTH RESPONSE IN RADISH TO SEQUENTIAL AND SIMULTANEOUS EXPOSURES OF NO2 AND SO2  

EPA Science Inventory

Sequential and simultaneous exposures of radish Raphanus sativus L. cv. Cherry Belle to 0.8 microliters per liter nitrogen dioxide (NO2) and 0.8 microliters per liter sulphur dioxide (SO2) were conducted under both day- and night-time conditions to examine the effects on growth a...

6

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

Code of Federal Regulations, 2011 CFR

... Test procedures for methods for SO2, CO, O3, and NO2. 53.32 Section 53... Test procedures for methods for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2 methods when the...

2011-07-01

7

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

Code of Federal Regulations, 2010 CFR

... Test procedures for methods for SO2, CO, O3, and NO2. 53.32 Section 53... Test procedures for methods for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2 methods when the...

2010-07-01

8

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

SciTech Connect

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

Michael Grutzeck

1999-04-30

9

SO2 REMOVAL FROM FLUE GASES USING UTILITY SYNTHESIZED ZEOLITES  

SciTech Connect

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

MICHAEL GRUTZECK

1998-10-31

10

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

11

Observations of SO2 and NO2 by mobile DOAS in the Guangzhou Eastern Area during the Asian Games 2010  

NASA Astrophysics Data System (ADS)

Mobile 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. Spatial and temporal distributions of SO2 and NO2 in this area were obtained and emission sources were determined by using wind field data. The NO2 vertical column densities were found to agree with OMI values. The correlation coefficient (R2) was 0.88 after cloud filtering. During the Guangzhou Asian Games and Asian Paralympics (Para) Games, the SO2 and NO2 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 NO2 emission was estimated to be 3.50 ± 1.89 tons per hour. During the phases of the Asian and Asian Para Games, the SO2 and NO2 emissions were reduced by 53.5 and 46%, 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.

2013-01-01

12

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

NASA Technical Reports Server (NTRS)

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

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

1994-01-01

13

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

14

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

E-print Network

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

Williams-Jones, Glyn

15

Modifications of Phleum pratense grass pollen allergens following artificial exposure to gaseous air pollutants (O3, NO2, SO2)  

E-print Network

to gaseous air pollutants (O3, NO2, SO2) Rogerieux F.1 , Godfrin D.2,4,* , Sénéchal H.2,3,* , Motta A.C.5: Air pollution and pollen allergens. Key words: traffic-related pollution, grass pollen, allergen, two - Abstract Background: Air pollution is frequently proposed as a potential cause for the increased incidence

Paris-Sud XI, Université de

16

Modifications of Phleum pratense Grass Pollen Allergens following Artificial Exposure to Gaseous Air Pollutants (O3, NO2, SO2)  

Microsoft Academic Search

Background: Air pollution is frequently proposed as a potential cause of the increased incidence of allergy in industrialised countries. Our objective was to investigate the impact of the major gaseous air pollutants on grass pollen allergens. Methods: Timothy grass pollen was exposed to ozone (O3), nitrogen dioxide (NO2) and sulphur dioxide (SO2) alone or in combination. Allergen contents were analysed

F. Rogerieux; D. Godfrin; H. Sénéchal; A. C. Motta; M. Marlière; G. Peltre; G. Lacroix

2007-01-01

17

Physicochemical damage parameters for the action of SO 2 and NO 2 on single pieces of marble  

NASA Astrophysics Data System (ADS)

The theoretical analysis for measurement of building-damage parameters by RF-GC technique is applied to the action of SO 2 and NO 2 on marble. The experiments with SO 2 were performed with five different geometric forms of single pieces of marble at 373.2 K and were repeated after washing these pieces 8 times with three-distilled water. All six physicochemical parameters determined show negligible variations for the same solid form at the same temperature, but they are different for the various geometrical forms. The mass transfer coefficients Kg and Ks and their ratio K seem to be the most invariant parameters with respect to the form. After washing with water, some of the parameters change considerably. The action of NO 2 was studied on a sphere only, but at five different temperatures. The physicochemical parameters for the action of this gas are three orders of magnitude smaller than those of SO 2 (except K), leading to 3700 times bigger resistance of marble to mass transfer of NO 2 than of SO 2. From the variation of the parameters with temperature, it is concluded that both mass transfer coefficients, Kg and Ks, pertain to activated processes with activation energies 39 and 27 kJ mol -1, respectively. The reaction of the adsorbed gas with the solid is less activated, whereas the adsorption equilibrium constant K does not change with temperature.

Vassilakos, Ch; Katsanos, N. A.; Niotis, A.

18

[Trail use of new phytoindicators in connection with passive sampling of traffic air pollution monitoring [especially for (synergistic) effects NO2 and SO2  

PubMed

Introduced research was connected with exposure of liverword Marchantia polymorpha in selected places in the area of Krakow. Places differing in regard to average concentration of air pollution [especially for (synergistic) effects NO2 and SO2]. Purpose of research was to check correlation between exposure to different concentrations of NO2 and SO2 (in regard to their synergistic effects) and possible differences in dynamics of growth of M. polymorpha. Samples of M. polymorpha located in soil, which was standardly analysed (in regard to contents of trace elements) before and after exposure. Research was simultaneously performed with similar exposure culture in vitro of Petunia hybrida. To growing tissues of petunia was used standard Murashige & Skoog medium and was protected against infections (with using filter of fibre). Described biomonitoring was completed by measurements of concentration of NO2 and SO2 by passive method with use of samplers of Amaya and Krochmal, in the same places, where was located exposure of plants. Observed was inhibition of growth in places, where was high concentration both gases. PMID:15682941

Bach, Anna; Warcho?, Marzena; Gowin, Katarzyna

2004-01-01

19

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

20

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

NASA Technical Reports Server (NTRS)

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

Guo, Song; Zhou, Xiuji; Zhang, Xiachun

1994-01-01

21

Effect of exposure to O3, NO 2, and SO 2 on chronic obstructive pulmonary disease hospitalizations in Tabriz, Iran.  

PubMed

Air pollution in cities is a serious environmental problem especially in the developing countries. We examined the associations between gaseous pollutants and hospitalizations for chronic obstructive pulmonary diseases (COPD) among people living in Tabriz, a city in north western of Iran. We used the approach proposed by the World Health Organization (WHO) using the AirQ 2.2.3 software developed by the WHO European Center for Environment and Health, Bilthoven Division. To assess human exposure and health effect, data were used for ozone as a1h average; for nitrogen dioxide and sulfur dioxide as daily average concentrations. The association between air pollution and chronic obstructive pulmonary disease (COPD) was assessed using AirQ 2.2.3 model. The results of this study showed that 3 % (95 % CI 1.2-4.8 %) of HA COPD were attributed to O3 concentrations over 10 ?g/m(3). Also, 0.9 % (95 % CI 0.1-2.2 %) and 0.4 % (95 % CI 0-1.1 %) of HA COPD were attributed to NO2 and SO2 concentrations over 10 ?g/m(3), respectively. For every 10 ?g/m(3) increase in O3, NO2, and SO2 concentrations, the risk of HA COPD increase to about 0.58, 0.38, and 0.44 %, respectively. We found significant positive associations between the levels of all air pollution and hospital admissions COPD. Otherwise, O3, NO2, and SO2 have a significant impact on COPD hospitalization. PMID:25217280

Ghozikali, Mohammad Ghanbari; Mosaferi, Mohammad; Safari, Gholam Hossein; Jaafari, Jalil

2015-02-01

22

Self-, air, and noble gas broadening in rotational-vibrational bands of SO2, H2S, and NO2  

NASA Astrophysics Data System (ADS)

Beside the knowledge of line positions and strengths precise data on the line broadening are prerequisite for the analysis of atmospheric transmission spectra and the in-situ determination of trace gas concentrations. Moreover, experimental data on the line broadening provide information on the collision processes as origin of broadening and shift of absorption lines. In this paper result on the line broadening obtained with a pulse driven diode laser spectrometer are presented. Intensive studies of the self- broadening were carried out for the v1, v3, and v1 plus v3 bands of SO2, the v1, v2, v3, and 2v2 bands of H2S, and the v3 band of NO2 in order to analyze the quantum number dependence of the broadening coefficients. For SO2 a pronounced decrease of the broadening coefficients with increasing quantum number Kan was found. In the case of H2S the Jn-dependence dominates, whereas in the case of NO2 a trend is not obvious. To study the perturber dependence of the broadening, air, He, Ne, Ar, Kr, and Xe were included in the experiments. The tendencies observed for noble gas perturbers could be described theoretically with a modified Anderson-Tsao-Curnutte-theory.

Sumpf, Bernd

1997-03-01

23

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

Code of Federal Regulations, 2010 CFR

...Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection...Suggested Format for Reporting Test Results for Methods for SO 2 , CO, O 3 , NO 2 Candidate Method Reference Method...

2010-07-01

24

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, 2011 CFR

...Suggested Format for Reporting Test Results for Methods for SO 2, CO, O 3, NO 2 C Figure C-1 to Subpart C of Part 53 Protection...Suggested Format for Reporting Test Results for Methods for SO 2 , CO, O 3 , NO 2 Candidate Method Reference Method...

2011-07-01

25

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

26

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

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

27

Simultaneous treatment of SO2 containing stack gases and waste water  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

28

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

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

29

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

30

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

31

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

32

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

NASA Astrophysics Data System (ADS)

Benzene, toluene, sulphur dioxide, ozone and nitrogen dioxide were measured at a mean level of 13.5 m above ground in a narrow, four-lane street canyon (height 30 m, width 20 m) in Thessaloniki, Greece during the period January-July 1997 by means of a commercial differential optical absorption spectrometer (OPSIS DOAS). Primary pollutant levels were found to be 2.5-4.4 times higher during the cold part of the year than during the warm part of the year, the winter/summer ratio increasing with the reaction rate constant with OH for each of the measured species. Ozone, on the other hand, exhibited a winter/summer ratio of 0.36. NO 2 originates from both primary and secondary sources; its winter/summer concentration ratio of 1.4 lies, therefore, between those of primary pollutants and ozone. Pollution levels were influenced considerably by wind speed, while for the street canyon under study wind direction did not influence pollutant levels considerably. While primary pollution was found to decrease with increasing wind speed, ozone increased. Benzene mean levels during the study period were around 6 ppb and hence much higher than the EU annual limit value of 5 ?g m -3 (1.44 ppb at STP). Toluene mean levels were around 14 ppb and hence also several times above the WHO recommendation of 2 ppb for 24 h. The apportionment of traffic emissions in four time zones used in most inventories in urban airshed models was tested using benzene and toluene measurements at low (<1 m s -1) wind speeds. The agreement between model emissions and calculated emissions apportionment into the four time zones was good, except for Zone D (23:00-1:59), where model inventory emissions were somewhat too low.

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

33

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

NASA Astrophysics Data System (ADS)

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

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

2015-02-01

34

Roles of supports, Pt loading and Pt dispersion in the oxidation of NO to NO 2 and of SO 2 to SO 3  

Microsoft Academic Search

Three types of platinum catalysts, Pt\\/SiO2, Pt\\/?-Al2O3 and Pt\\/ZrO2 were examined for the oxidation of NO to NO2 of SO2 to SO3. The activity order for both oxidation reactions was found to be: Pt\\/SiO2>Pt\\/?-Al2O3>Pt\\/ZrO2. The effect of Pt loading and Pt dispersion on the catalytic activity and selectivity was examined. Over Pt\\/SiO2, the specific activities were found to be strongly

E. Xue; K. Seshan; J. R. H. Ross

1996-01-01

35

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

PubMed Central

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

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

2014-01-01

36

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

37

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

PubMed Central

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

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

2013-01-01

38

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

39

Controlled exposure to a mixture of SO2, NO2, and particulate air pollutants: effects on human pulmonary function and respiratory symptoms  

Microsoft Academic Search

Exposure of 20 volunteers to sodium chloride (NaCl) aerosol or to a mixture containing NaCl plus irritant particles (zinc ammonium sulfate) and irritant gases (nitrogen dioxide and sulfur dioxide) produced no significant decrements in pulmonary function. There was a slight tendency for respiratory symptoms to be greater during the exposure to the mixture than during exposure to the NaCl aerosol

M. T. Kleinman; R. M. Bailey; J. D. Whynot; K. R. Anderson; W. S. Linn; J. D. Hackney

1985-01-01

40

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

EPA Science Inventory

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

41

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

USGS Publications Warehouse

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

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

1990-01-01

42

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

PubMed

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

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

2014-01-01

43

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

PubMed Central

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

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

2014-01-01

44

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

45

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

46

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

47

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

48

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

PubMed

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

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

2008-10-01

49

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

PubMed

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

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

2015-03-21

50

On the SO2 problem of solid fuel combustion  

NASA Astrophysics Data System (ADS)

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

Boyadjiev, Chr.

2014-09-01

51

Measurements of stratospheric SO2 after the EL Chichon eruptions  

NASA Technical Reports Server (NTRS)

Samples of stratospheric trace gases were obtained on eight flights of NASA high-altitude aircraft from April 16 through December 13, 1982. The sampling occurred at altitudes from 15 to 22 km, latitudes from 23 to 52 deg N, and longitudes from 108 to 130 deg W. The cryogenically concentrated samples were analyzed by gas chromatography for SO2, a primary precursor of the gas-to-particle conversion process. The measured mixing ratio of SO2 varied between 8 and 132 pptv. Evidence from aerosol measurements indicates that a few of our early samples may have been collected in the fringes of the volcanic cloud from El Chichon. Samples obtained on some later flights may have been from the eruption cloud but were taken at times when most of the volcanically injected SO2 should have been converted to H2SO4.

Vedder, J. F.; Condon, E. P.; Tabor, K. D.; Kritz, M. A.; Inn, E. C. Y.

1983-01-01

52

Investigation of flue-gas treatment with O 3 injection using NO and NO 2 planar laser-induced fluorescence  

Microsoft Academic Search

Direct ozone (O3) injection is a promising flue-gas treatment technology based on oxidation of NO and Hg into soluble species like NO2, NO3, N2O5, oxidized mercury, etc. These product gases are then effectively removed from the flue gases with the wet flue gas desulfurization system for SO2. The kinetics and mixing behaviors of the oxidation process are important phenomena in

Z. H. Wang; B. Li; A. Ehn; Z. W. Sun; Z. S. Li; J. Bood; M. Aldén; K. F. Cen

2010-01-01

53

The first climatology of stratospheric SO2  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

54

Observations of SO2 During NOMADSS  

NASA Astrophysics Data System (ADS)

Atmospheric sulfur dioxide, SO2, has both natural and anthropogenic sources. Both oxidation of marine dimethyl sulfide and volcanic emissions contribute to natural levels, while combustion of sulfur containing fuels and industrial processes further contribute to atmospheric concentrations. Here SO2 measurements from the recent NSF - NOMADSS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) study will be presented. A Thermo Scientific model 43i-TLE SO2 monitor was placed aboard the NCAR C-130 and provided a rich data set in SO2 with measurements in environments ranging from the clean troposphere, to both mixed and local sources of industrial SO2 emissions. Correlations with sulfuric acid concentrations were observed and when combined with OH concentrations, allow sulfuric acid production rates to be calculated for these various environments. The broad extent of the NOMADSS study also allows a comparison of overall SO2 levels observed over Texas and Alabama to be compared with those made over the Ohio River valley.

Schardt, N.; Mauldin, L.; Cantrell, C. A.

2013-12-01

55

CO2-SO2 clathrate hydrate formation on early Mars  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

56

Interspecific Variation in SO2 Flux 1  

PubMed Central

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

Olszyk, David M.; Tingey, David T.

1985-01-01

57

A study of the adsorption of NH 3 and SO 2 on leaf surfaces  

NASA Astrophysics Data System (ADS)

The adsorption of NH 3 and SO 2 on the external leaf surface of bean ( Phaseolus vulgaris L.) and poplar ( Populus euramericana L.) was studied. The adsorbed quantities increased strongly with increasing air humidity, indicating that water on the leaf surface plays a major role in the interaction of these gases with the leaf surface. On the other hand temperature in the range between 15 and 26°C had no significant influence. The adsorbed quantities of NH 3 at a specific air humidity appeared to be proportional to NH 3 concentration. This proportionality was less clear for SO 2. The affinity of SO 2 for the leaf surface was found to be approximately twice that of NH 3. A mixture of these gases in the air mutually stimulated their adsorption on the leaf. No significant desorption or uptake of these gases through the cuticle could be detected, indicating that the bulk of the adsorbed gases remains associated with the cuticle.

Van Hove, L. W. A.; Adema, E. H.; Vredenberg, W. J.; Pieters, G. A.

58

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...

59

ADVANCED CONCEPTS: SO2 REMOVAL PROCESS IMPROVEMENTS  

EPA Science Inventory

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

60

SO2 SCRUBBING TECHNOLOGIES: A REVIEW  

EPA Science Inventory

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

61

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), ...

62

SO(2, 3) noncommutative gravity model  

NASA Astrophysics Data System (ADS)

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

Dimitrijevi?, M.; Radovanovi?, V.

2014-12-01

63

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

64

High SO2 Removal Efficiency Testing  

SciTech Connect

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

Gary Blythe

1997-07-29

65

Comparative study of the reactions of metal oxides with H2S and SO2  

Microsoft Academic Search

The primary objective of this project is the investigation of the effects of pore structure on the capacity of porous metal oxides for removal of gaseous pollutants from flue gases of power plants (SO2) and hot coal gas (primarily H2S). Specifically, we intend to appropriately exploit the differences of the sulfidation and sulfation reactions (for instance, different molar volumes of

S. V. Sotirchos

1991-01-01

66

76 FR 69051 - Final Response to Petition From New Jersey Regarding SO2  

Federal Register 2010, 2011, 2012, 2013, 2014

...and that SO 2 is a precursor to acid rain formation and fine sulfate particle...have undertaken as a result of the acid rain program and the Clean Air Interstate...pollutants, including existing sources of acid gases (e.g., hydrogen...

2011-11-07

67

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

NASA Astrophysics Data System (ADS)

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

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

2004-04-01

68

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

69

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

E-print Network

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

Weidner, John W.

70

High frequency SO2 flux measurements at Semeru volcano, Indonesia, using the SO2 camera  

NASA Astrophysics Data System (ADS)

SO2 monitoring is a common technique at many volcanic centers. Recently, automated networks of scanning spectrometers have led to great improvement in frequency and accuracy of measurements. Simultaneously a new instrument has been proposed to acquire 2D images of volcanic plumes in the UV spectrum. This imaging technique (hereafter referred to as the SO2 camera) provides additional contextual information, as well as a quantitative way of determining plume velocity from a single remote location, without relying on weather reports. These advantages are to be balanced against a loss of spectroscopic information associated with using band-pass filters that reduce precision in the measurements. We have developed a custom-built acquisition and processing software to be used with the SO2 camera developed by INGV-Pisa for monitoring of Etna and Stromboli, which consists of two Quantum Scientific Imaging CCD cameras equipped with UV filters and a USB2000+ spectrometer. We have tested the instrument at two power plants in Arizona, USA. We were able to successfully measure SO2 fluxes as low as 1-2 tons/day. We also validated our method by comparing the SO2 camera measurements against high-frequency in-situ measurements (1 data point every minute) obtained from chemical sensors within the stacks. We have also used the SO2 camera during a field campaign at Semeru volcano, Indonesia, in May and June of 2013. Semeru is a persistently active explosive volcano, whose latest eruption began in 1967. Its eruptive behavior can be characterized by cyclic dome growth and collapse in the active crater and frequent small magnitude explosions occurring at periods of minutes to hours. We found that the majority of SO2 at Semeru is released during the explosive phases (instantaneous peaks of up to 40 kg/s), with passive emission levels between explosions fluctuating from 0-5 kg/s. After the initial explosive release, emission returns to background levels following an exponential decline over a period of 10-15 mins, often punctuated by several secondary gas-release pulses. Based on the eruptive freqeuency we observed at the time of measurement (1 explosion every 30-60 mins), we estimate the average SO2 flux from Semeru to be 300-400 tons/day, depending on the magnitude of individual explosions. To interpret the data in terms of magma ascent we also used DOMEFLOW, a 1.5D transient isothermal numerical model. Petrologic observations from tephra and ballistic samples collected at the summit help us constrain the initial conditions of the system, including the volatile content. Preliminary model runs produced periodic lava extrusion and pulses of gas release at the vent, with a cycle period on the order of hours, even though a steady magma supply rate was prescribed at the bottom of the conduit. Enhanced shallow permeability creates a dense plug in the shallow subsurface, which in turn plays a critical role in creating and controlling the observed periodic behavior.

Smekens, J.; Burton, M. R.; Clarke, A. B.; Harijoko, A.; Wibowo, H.; Sawyer, G.

2013-12-01

71

LIMITED SO2 AND NOX MEASUREMENTS IN ST. LOUIS, 1974: VOLUME I - PLUME TRACKING BY CORRELATION SPECTROSCOPY  

EPA Science Inventory

A Barringer COSPEC spectrophotometer was used to measure the total overhead burden of SO2 and NO2 in the St. Louis urban plume and in the plumes of specific power plants in the St. Louis area. This information was combined with meteorological data to calculate SO2 fluxes in the p...

72

HISTORIC SO2 AND NOX EMISSIONS ESTIMATES (FOR MICROCOMPUTERS)  

EPA Science Inventory

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

73

Relative Sensitivity of Wetland Plants to SO 2 Pollution  

Microsoft Academic Search

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

Chenyan Sha; Tianhui Wang; Jianjian Lu

2010-01-01

74

SO2 SCRUBBING IN A TAPERED BUBBLE COLUMN SCRUBBER  

Microsoft Academic Search

SO2 emissions from various sources are found to occur in various concentrations and quantities. Abatement of SO2 emission, therefore, assumes significant importance over the decades. Wet scrubbers offer great advantage over other devices for gas cleaning. That is the reason that compliance with SO2 standards will in many cases result in the installation of scrubbing devices. This article presents results

Amitava Bandyopadhyay; Manindra Nath Biswas

2006-01-01

75

COAL CLEANING OPTIONS FOR SO2 EMISSION REDUCTION  

EPA Science Inventory

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

76

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

77

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

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

78

Vertical distribution of volcanic SO2 retrieved from IASI.  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

79

A Balloon Sounding Technique for Measuring SO2 Plumes  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

80

Regional climatic effects of atmospheric SO2 on Mars  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

81

A study of the N2O5-SO2-O3 reaction system.  

PubMed

Infrared spectroscopy was used to follow the rates of the chemical changes in gaseous N(2)O(5)-SO(2) and N(2)O(5)-SO(2)-O(3) mixtures. Several results of interest to atmospheric scientists were obtained. (I) SO(3) was not a detectable product of these reaction systems, and no significant SO(2) removal occurred. From the kinetic treatment of these results, estimates were derived for the upper limits of the rate constants of the reactions 1 and 2: NO(3) + SO(2) leads to NO(2) + SO(3) (1); N2O5 +SO2 leads to N(2)O(4) + SO(3) (2); k(1) less than or equal to 4.2 1. mole-minus 1sec-minus 1; k(2) less than or equal to 2.5 x 10-minus 2 1. mole-minus1sec-minus 1 at 30 degrees C. These data suggest that reactions 1 and 2 are not important removal paths for SO(2) in the sunlight irradiated, NO(x)hydrocarbon polluted atmospheres. (II) The near ultraviolet absorption spectrum of pure N(2)O(5) has been determined. From these results and estimates of the actinic irradiance, it was shown that the rate of photochemical decomposition of N(2)O(5) by the absorption of solar light in the urban atmosphere is an unimportant factor among the reactions which establish the N(2)O(5) and NO(3) concentrations. (III) It has been observed that gaseous SO(3) and NO(2) react rapidly to form a relatively nonvolatile white solid. Preliminary data suggest a 1:1 mole ratio for this adduct. The significance, if any, of this and related compounds in urban aerosol formation must be evaluated. PMID:1132385

Daubendiek, R L; Calvert, J G

1975-01-01

82

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 ...

83

LOW NOX COMBUSTION SYSTEMS WITH SO2 CONTROL USING LIMESTONE  

EPA Science Inventory

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

84

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

2013-11-01

85

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...

86

ACCURACY OF REMOTELY SENSED SO2 MASS EMISSION RATES  

EPA Science Inventory

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

87

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

SciTech Connect

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

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

2013-01-17

88

Thermophilic biofilter for SO2 removal: Performance and microbial characteristics.  

PubMed

A bench-scale thermophilic biofilter was applied to remove SO2 at 60°C in the present study. The SO2 concentration in the inlet stream ranged from 100mg/m(3) to 200mg/m(3). An average SO2 removal efficiency of 93.10% was achieved after developing acclimated organisms that can degrade SO2. The thermophilic biofilter effectively reduced SO2, with a maximum elimination capacity of 50.67g/m(3)/h at a loading rate of 51.44g/m(3)/h. Removal efficiency of the thermophilic biofilter was largely influenced by the water containing rate of the packing materials. The SO2 transfer in the biofilter included adsorption by the packing materials, dissolution in liquid, and microbial degradation. The main product of SO2 degradation was SO4(2-). The temporal shifts in the bacterial community that formed in the biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and DNA sequence analysis. These shifts revealed a correlation between biofilter performance and bacterial community structure. PMID:25594505

Zhang, Jingying; Li, Lin; Liu, Junxin

2015-03-01

89

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

90

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

91

Synthetic Assessment of Historical Anthropogenic Sulfur Dioxide (SO2) Emissions  

E-print Network

and climate change since industrial revolution. · This study assesses the original researches on historical 1850, anthropogenic SO2 emissions were distributed mostly by open burning sources and industrial

92

Supply of SO2 for the atmosphere of Io  

NASA Astrophysics Data System (ADS)

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

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

1983-02-01

93

SO2-rich equatorial basins and epeirogeny of Io  

NASA Technical Reports Server (NTRS)

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

Mcewen, Alfred S.

1991-01-01

94

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

95

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

96

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

97

Special Polymer/Carbon Composite Films for Detecting SO2  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

98

Greenhouse Gases  

MedlinePLUS

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

99

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

100

Contribution of SO2 to antioxidant potential of white wine.  

PubMed

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

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

2015-05-01

101

Light-Induced SO2 Photochemistry at the Mineral Dust Surface  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

102

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

103

Measuring SO2 ship emissions with an ultraviolet imaging camera  

NASA Astrophysics Data System (ADS)

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

Prata, A. J.

2014-05-01

104

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

E-print Network

altitude or above the plume mask the SO2 signal. (see Carboni et all 2012) - Comparison with other1 Volcanic sulphur dioxide (SO2) in atmosphere from IASI data: analysis of SO2 amount and altitude estimate of stare vector: SO2 amount, plume altitude, Ts State vector: - Total column amount of SO2

Oxford, University of

105

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...

106

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...

107

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/...

108

BOILER SIMULATOR STUDIES ON SORBENT UTILIZATION FOR SO2 CONTROL  

EPA Science Inventory

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

109

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...

110

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

E-print Network

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

111

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...

112

EVALUATION OF SIMULTANEOUS SO2/NOX CONTROL TECHNOLOGY  

EPA Science Inventory

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

113

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...

114

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...

115

SO2 SCRUBBING TECHNOLOGIES: A REVIEW: JOURNAL ARTICLE  

EPA Science Inventory

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

116

Transport of SO 2 and aerosol over the Yellow sea  

Microsoft Academic Search

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

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

2001-01-01

117

Correlations between stream sulphate and regional SO2 emissions  

USGS Publications Warehouse

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

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

1986-01-01

118

Soil acidification in China: is controlling SO2 emissions enough?  

PubMed

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

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

2009-11-01

119

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

120

Towards AN Accurate Infrared Linelist for SO{_2}  

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

121

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

122

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

PubMed

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

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

2011-01-01

123

NOBLE GASES  

EPA Science Inventory

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

124

Manure Gases  

MedlinePLUS

... of manure. The gases of most concern are ammonia and hydrogen sulfide. Other gases of concern include ... in low areas of manure storage or accumulation. Ammonia, which is lighter than air, is found above ...

125

Market Opportunities for Austenitic Stainless Steels in SO2 Scrubbers  

NASA Astrophysics Data System (ADS)

Recent U.S. federal legislation has created new opportunities for SO2 scrubbers because all coals, even low-sulfur western coals, will probably require scrubbing to remove SO2 from gaseous combustion products. Scrubbing, the chemical absorption of SO2 by vigorous contact with a slurry—usually lime or limestone—creates an aggressive acid-chloride solution. This presents a promising market for pitting-resistant austenitic stainless steels, but there is active competition from rubber and fiberglass-lined carbon steel. Since the latter are favored on a first-cost basis, stainless steels must be justified on a cost/performance or life-cost basis. Nickel-containing austenitic alloys are favored because of superior field fabricability. Ferritic stainless steels have little utility in this application because of limitations in weldability and resulting poor corrosion resistance. Inco corrosion test spools indicate that molybdenum-containing austenitic alloys are needed. The leanest alloys for this application are 316L and 317L. Low-carbon grades of stainless steel are specified to minimize corrosion in the vicinity of welds. More highly alloyed materials may be required in critical areas. At present, 16,000 MW of scrubber capacity is operational and 17,000 MW is under construction. Another 29,000 MW is planned, bringing the total to 62,000 MW. Some 160,000 MW of scrubber capacity is expected to be placed in service over the next 10 years. This could translate into a total potential market of 80,000 tons of alloy plate for new power industry construction in the next decade. Retrofitting of existing power plants plus scrubbers for other applications such as inert gas generators for oil tankers, smelters, municipal incinerators, coke ovens, the pulp and paper industry, sulfuric acid plants, and fluoride control in phosphoric acid plants will add to this large market.

Michels, Harold T.

1980-10-01

126

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

127

Mineral dust photochemistry induces nucleation events in the presence of SO2  

PubMed Central

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 SO2 to H2SO4 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

2012-01-01

128

Behaviors of SO 2 absorption in [BMIm][OAc] as an absorbent to recover SO 2 in thermochemical processes to produce hydrogen  

Microsoft Academic Search

The solubility behavior of SO2 in 1-butyl-3-methylimidazolium acetate ([BMIm][OAc]) was investigated. The solubility of SO2 in [BMIm][OAc] was measured to be 0.6 in mole fraction at 50°C in a stream of SO2 gas. The desorption of SO2 from [BMIm][OAc] was never completed, until the temperature was raised to 170°C in a stream of N2, indicating that the absorption of SO2

Ki Yong Lee; Hoon Sik Kim; Chang Soo Kim; Kwang-Deog Jung

2010-01-01

129

Spatial mapping of ozone and SO2 trends in Europe.  

PubMed

This article investigates the spatial mapping of temporal trends in air quality for all of Europe. Such spatially distributed maps provide information for policy making and for understanding the spatial character of air quality trends. Previous trend studies have concentrated on individual, or groups of, monitoring sites looking at the trends of these. In this study use is made of statistical interpolation methods that combine observed and modelled data in an optimised way. Log-normal residual kriging with multiple linear regression is used to produce annual maps of air quality indicators for ozone (AOT40; Accumulated Dose of Ozone Over a Threshold of 40 ppb) and SO(2) (annual mean) for the period 1996-2005. Trends in these maps are then calculated and their significance and uncertainty are assessed. The methodology is effectively used for mapping SO(2) trends to a significant level in most of Europe. However, trends in AOT40 are less clearly defined since the uncertainty is generally of the same order as, or greater than, the calculated trends. A general north to south gradient in AOT40 trends can be seen, with downward trends in the UK and Scandinavia but upward trends in the Mediterranean region. PMID:20619880

Denby, Bruce; Sundvor, Ingrid; Cassiani, Massimo; de Smet, Peter; de Leeuw, Frank; Horálek, Jan

2010-09-15

130

Study of meteorological aspects and urban concentration of SO2 in atmospheric environment of La Plata, Argentina.  

PubMed

This article presents and discusses SO(2) (ppbv) concentration measurements combined with meteorological data (mainly wind speed and direction) for a five-year campaign (1996 to 2000), in a site near an oil refinery plant close to the city of La Plata and surroundings (aprox. 740.000 inh.), considered one of the six most affected cities by air pollution in the country. Since there is no monitoring network in the area, the obtained results should be considered as medium term accumulated data that enables to determine trends by analyzing together gas concentrations and meteorological parameters. Preliminary characterization of the behaviour of the predominant winds of the region in relation with potential atmospheric gas pollutants from seasonal wind roses is possible to carry out from the data. These results are complemented with monthly averaged SO(2) measurements. In particular, for year 2000, pollutant roses were determined which enable predictions about contamination emission sources. As a general result we can state that there is a clear increase in annual SO(2) concentration and that the selected site should be considered as a key site for future survey monitoring network deployment. Annual SO(2) average concentration and prevailing seasonal winds determined in this work, together with the potential health impact of SO(2) reveals the need for a comprehensive and systematic study involving particulate matter an other basic pollutant gases. PMID:16741788

Ratto, Gustavo; Videla, Fabián; Almandos, J Reyna; Maronna, Ricardo; Schinca, Daniel

2006-10-01

131

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

2012-02-01

132

Reduction of SO(2) symmetry for spatially extended dynamical systems  

E-print Network

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

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

2015-01-16

133

Precursor gases of aerosols in the Mount St. Helens eruption plumes at stratospheric altitudes  

NASA Technical Reports Server (NTRS)

Nineteen stratospheric samples from the eruption plumes of Mount St. Helens were collected in five flight experiments. The plume samples were collected at various altitudes from 13.1 to 20.7 km by using the Ames cryogenic sampling system on board the NASA U-2 aircraft. The enriched, cryogenically collected samples were analyzed by chromatography. The concentrations of aerosols precursor gases (OCS, SO2, and CS2), CH3Cl, N2O, CF2Cl2, and CFCl3 were measured by gas chromatography. Large enhancement of the mixing ratio of SO2 and moderate enhancement of CS2 and OCS were found in the plume samples compared with similar measurement under pre-volcanic conditions. A fast decay rate of the SO2 mixing ratio in the plume was observed. Measurement of Cl(-), SO2(2-), and NO3(-) by ion chromatography was also carried out on water solutions prepared from the plume samples. The results obtained with this technique imply large mixing ratios of HCl, (NO + NO2 + HNO3), and SO2, in which these constituents are the respective sources of the anions. Measurement of the Rn222 concentration in the plume was made. Other stratospheric constituents in the plume samples, such as H2O, CO2, CH4, and CO, were also observed.

Inn, E. C. Y.; Vedder, J. F.; Condon, E. P.; Ohara, D.

1982-01-01

134

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

135

Broadband UV spectroscopy system used for monitoring of SO 2 and NO emissions from thermal power plants  

NASA Astrophysics Data System (ADS)

A gas monitoring system based on broadband absorption spectroscopic techniques in the ultraviolet region is described and tested. The system was employed in real-time continuous concentration measurements of sulfur dioxide (SO 2) and nitric oxide (NO) from a 220-ton h -1 circulating fluidized bed (CFB) boiler in Shandong province, China. The emission coefficients (per kg of coal and per kWh of electricity) and the total emission of the two pollutant gases were evaluated. The measurement results showed that the emission concentrations of SO 2 and NO from the CFB boiler fluctuated in the range of 750-1300 mg m -3 and 100-220 mg m -3, respectively. Compared with the specified emission standards of air pollutants from thermal power plants in China, the values were generally higher for SO 2 and lower for NO. The relatively high emission concentrations of SO 2 were found to mainly depend on the sulfur content of the fuel and the poor desulfurization efficiency. This study indicates that the broadband UV spectroscopy system is suitable for industrial emission monitoring and pollution control.

Zhang, Y. G.; Wang, H. S.; Somesfalean, G.; Wang, Z. Y.; Lou, X. T.; Wu, S. H.; Zhang, Z. G.; Qin, Y. K.

2010-11-01

136

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

NASA Technical Reports Server (NTRS)

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

Hoell, J. M., Jr.

1975-01-01

137

Kinetics of the reaction HO2 + NO2 + M yields HO2NO2 + M  

NASA Technical Reports Server (NTRS)

The flash photolysis/ultraviolet absorption technique was used to measure the rate constants for the reaction HO2 + NO2 + M yields HO2NO2 + M over the pressure range 50-700 torr and temperature range 229-362 K using He, O2, and N2 as diluent gases. The data were fit to the expression derived by Troe (1979) and co-workers for describing the pressure and temperature dependence of reactions in the falloff region. By combining these data with recent measurements of the rate constant for HO2NO2 thermal decomposition values of 73.8 + or - 2 eu for the standard entropy and -12.6 + or - kcal/mol for the standard enthalpy of formation of HO2NO2 were obtained. A significant enhancement in the rate constant was observed when water vapor was added to the system.

Sander, S. P.; Peterson, M. E.

1984-01-01

138

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...

139

Screening of inorganic gases released from firework-rockets by a gas chromatography/whistle-accelerometer method.  

PubMed

The use of an accelerometer for detecting inorganic gases in gas chromatography (GC) is described. A milli-whistle was connected to the outlet of the GC capillary and was used instead of a classical GC detector. When the GC carrier gases and the sample gases pass through the milli-whistle, a sound is produced, leading to vibrational changes, which can be recorded using an accelerometer. Inorganic gases, including SO2, N2 and CO2, which are released from traditional Chinese firework-rockets at relatively high levels as the result of burning the propellant and explosive material inside could be rapidly determined using the GC/whistle-accelerometer system. The method described herein is safe, the instrumentation is compact and has potential to be modified so as to be portable for use in the field. It also can be used in conjunction with FID (flame ionization detector) or TCD (thermal conductivity detector), in which either no response for FID (CO2, N2, NO2, SO2, etc.) or helium gas is needed for TCD, respectively. PMID:23891209

Chen, Kuan-Fu; Wu, Hui-Hsin; Lin, Chien-Hung; Lin, Cheng-Huang

2013-08-30

140

Greenhouse Gases  

MedlinePLUS

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

141

New SO(2) Iron-Containing Cluster Compounds [PPN](2)[Fe(3)(CO)(9)(&mgr;(3),eta(2)-SO(2))], [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))&mgr;(3)-S], [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))(&mgr;(3)-CCO)], and [PPN](2)[Fe(2)(CO)(6)(&mgr;-SO(2))(2)] from Heterometal Precursors.  

PubMed

Sulfur dioxide reacts with [PPN](2)[MFe(3)(CO)(14)] (M = Cr, Mo, W) (PPN = bistriphenylphosphonium iminium) to produce [PPN](2)[Fe(3)(CO)(9)(&mgr;(3),eta(2)-SO(2))] (I) and [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))&mgr;(3)-S] (II), which were characterized by infrared spectroscopy, (13)C NMR, and X-ray crystallography. Further reaction of I with sulfur dioxide results in the formation of II in 48% yield. Reaction of SO(2) with [PPN](2)[Fe(4)(CO)(13)] yields [PPN](2)[Fe(2)(CO)(6)(&mgr;-SO(2))(2)] (III) which was characterized by infrared spectroscopy, (13)C NMR, mass spectrometry, and X-ray crystallography. One equivalent of sulfur dioxide with [PPN](2)[MFe(3)(CO)(14)C] (M = Cr, W) produces [PPN](2)[Fe(3)(CO)(8)(&mgr;-SO(2))(&mgr;(3)-CCO)] (IV), which on further reaction with SO(2) gives the known cluster [PPN](2)[Fe(3)(CO)(7)(&mgr;-SO(2))(2)(&mgr;(3)-CCO)] (V). An excess of sulfur dioxide with [MFe(3)(CO)(n)()C](x)()(-) (M = Cr, W: n =13, x = 2; M = Rh: n = 12, x = 1; M = Mn: n = 13, x = 1) produced V as the only identified product. Crystallographic data for I.0.5CH(2)Cl(2): monoclinic, Cc (no. 9), a = 29.7648(3) Å, b = 14.6496(1) Å, c = 21.7620(3) Å, beta = 123.397(1) degrees, V = 7922.3 Å(3); Z = 4. Crystallographic data for III.NCCH(3): monoclinic P2(1) (no. 4), a = 10.0295(5) Å, b = 26.356(1) Å, c = 14.1032(7) Å, beta = 94.691 degrees, V = 3715.6(3) Å(3); Z = 4. PMID:11670914

Eveland, R. W.; Raymond, C. C.; Albrecht-Schmitt, T. E.; Shriver, D. F.

1999-03-22

142

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

EPA Science Inventory

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

143

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

EPA Science Inventory

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

144

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

E-print Network

for formation and release of odorous H2S.6-8 The addition of basic oxides, like baria, into three-way catalystChemistry of Sulfur Oxides on Transition Metals. III. Oxidation of SO2 and Self-Diffusion of O, SO2 Pt SO3(g) are studied using first-principles density functional theory (DFT). The diffusion processes

Lin, Xi

145

Plasma Chemistry and Plasma Processing, Vol. 12, No. 4, 1992 Removal of SO2 and the Simultaneous Removal of SO2  

E-print Network

Plasma Chemistry and Plasma Processing, Vol. 12, No. 4, 1992 Removal of SO2 and the Simultaneous gas-phase oxidation processes. This paper discusses dielectric barrier discharge (DBD) plasmas, also Removal of SO2 and NO from Simulated Flue Gas Streams Using Dielectric Barrier Discharge Plasmas Moo Been

Kushner, Mark

146

A comparison of observed and parameterized SO2 dry deposition over a grassy clearing in Duke Forest  

NASA Astrophysics Data System (ADS)

Deposition of trace gases, such as sulfur dioxide (SO2), can affect plant and soil chemistry in different ecosystems. Measurements over a complex ecosystem, like a forest clearing, are necessary to determine more accurate deposition rates that can be used to improve parameterizations and models. The flux-gradient technique was used to determine SO2 fluxes over grass in a clearing at Duke Forest, North Carolina, USA on 25 June - 2 July 2008. The mean flux was -0.037 ± 0.024 ?g m-2 s-1. Dew on the canopy enhanced the uptake of SO2, which increased deposition rates. Deposition velocities (Vd) fluctuated greatly with a mean of 1.00 ± 0.48 cm s-1. The large variation in Vd was not fully captured by estimates determined from a multilayer model (MLM) and a big-leaf model (BLM). Mean deposition velocities derived from the MLM and BLM were 1.25 ± 0.21 cm s-1 and 0.63 ± 0.12 cm s-1, respectively. The model estimations of Vd in this study were probably affected by uncertainties associated with canopy resistance, particularly with stomatal and non-stomatal processes.

Myles, LaToya; Heuer, Mark W.; Meyers, Tilden P.; Hoyett, Zakiya J.

2012-03-01

147

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

NASA Astrophysics Data System (ADS)

Volcanic gas emissions play a crucial role in describing geophysical processes; hence, measurements of magmatic gases such as SO2 can be used as tracers prior to and during volcanic crises. Different measurement techniques based on optical spectroscopy have provided valuable information when assessing volcanic crises. This paper describes the design and implementation of a network of spectroscopic instruments based on differential optical absorption spectroscopy (DOAS) for remote sensing of volcanic SO2 emissions, which is robust, portable and can be deployed in relatively short time. The setup allows the processing of raw data in situ even in remote areas with limited accessibility, and delivers pre-processed data to end users in near real time, even during periods of volcanic crisis, via a satellite link. In addition, the hardware can be used to conduct short-term studies of volcanic plumes in remote areas. We describe here tests of the network at Telica, an active volcano located in western Nicaragua, during three different measurement periods, including an eruptive crisis. The tests produced what is so far the largest data set of continuous SO2 flux measurements at this volcano. The measurements show that, during the period 2010-2013, the flux averages approximately 100 tons per day (t day-1).

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

2014-08-01

148

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

149

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

150

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

151

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...

152

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 ...

153

STRUCTURAL TRANSFORMATIONS IN CA-BASED SORBENTS USED FOR SO2 EMISSION CONTROL  

EPA Science Inventory

The paper discusses structural transformations in Ca-based sorbents used for SO2 emission control. conomizer temperature injection of Ca-based sorbents is an option for dry control of SO2 emissions from coal-fired boilers. heir reactivity with SO2 was found to be a function of th...

154

Comparison of seismic and SO2 time series recorded during eruptive phases of Tungurahua volcano (Ecuador) between 2010 and 2013  

NASA Astrophysics Data System (ADS)

Tungurahua is one of the most active volcanoes in Ecuador. It is a large andesitic stratovolcano which has been continuously erupting since 1999. Its activity has slightly changed since late 2009 and is now characterized by the occurrence of well-defined eruptive phases lasting from few weeks to months, separated by quiescence periods with a comparable duration range. Eruptive phases include the emission of ash and gases with the occurrence of Strombolian to Vulcanian explosions that can produce short runout pyroclastic flows. The monitoring networks operating on the volcano include 4 permanent DOAS instruments, 5 broadband seismic stations coupled with infrasound sensors and 5 short period seismometers. We examined the data from these instruments for the period 2010-2013 with the aim of looking for possible correlations between seismic and acoustic recordings and the amounts of SO2 emitted by the volcano. The seismicity related to eruptive/degassing processes is dominated by explosion quakes and longer duration tremors. To quantify both phenomena, we proceeded in two ways. First, we established the acoustic and seismic energies of individual explosions and calculated cumulative daily values. Secondly, to quantify the intensity of background tremor we calculated sliding median amplitudes in different frequency bands. On the other hand, NOVAC-1 type DOAS spectrometers operate during daylight only providing up to 140 daily measurements. Valid measurements are only obtained under good weather conditions, leading to irregular and sometimes sparse time series. Usually, daily average fluxes of SO2 are extrapolated from the available measurements. Alternately, we determined the daily observed SO2 masses by integrating all valid recordings during the 11 hours of daily measurement. This approach strongly reduces SO2 measured emissions during quiescence periods and provides time series having an improved correlation on a long time scale (years) with the eruptive phases of the volcano. However, on the time-scale of days to weeks, the comparison of the SO2 emissions with the seismo-acoustic parameters for the different eruptive phases between December 2009 and May 2013 outlines irregular correlations. Often temporal variations in SO2 emissions are poorly reproduced by both tremor and explosion amplitudes. When the vent is open SO2 emissions may be observed almost without producing any seismicity, at the beginning or during eruptive phases. Also, activity may shift from passive degassing to high explosive activity without any clear increase in SO2 emissions. When the conduit is closed, a sudden increase in seismicity, usually associated to Vulcanian explosions, is required to open the conduit and allow degassing. Rough qualitative correlations are sometimes observed between SO2 emissions and explosive activity, tremor and sometimes with both. Our results suggest that the relation between seismic activity and SO2 degassing may be strongly controlled by the conditions at the vent.

Battaglia, J.; Hidalgo, S.; Steele, A.; Arellano, S. R.; Ruiz, M. C.; Galle, B.

2013-12-01

155

Health Hazards from Volcanic Gases: A Systematic Literature Review  

Microsoft Academic Search

Millions of people are potentially exposed to volcanic gases worldwide, and exposures may differ from those in anthropogenic air pollution. A systematic literature review found few primary studies relating to health hazards of volcanic gases. SO2 and acid aerosols from eruptions and degassing events were associated with respiratory morbidity and mortality but not childhood asthma prevalence or lung function decrements.

Anna Hansell; Clive Oppenheimer

2004-01-01

156

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

NASA Astrophysics Data System (ADS)

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

Kumar, Ranjit; Maharaj Kumari, K.

2010-05-01

157

Ambient lithium-SO2 batteries with ionic liquids as electrolytes.  

PubMed

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

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

2014-02-17

158

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

159

Cross-sectional studies of plumes from a partially SO 2-scrubbed power plant  

NASA Astrophysics Data System (ADS)

An instrumented helicopter was used at the Tennessee Valley Authority (TVA) Widows Creek Steam Plant to collect a series of samples at several elevations within the plume at fixed distances downwind. During one segment of this study, much higher oxidation rates were observed in the lower part of the plume than in the upper part. These rates occurred on a day when the plume could be clearly separated into two parts. The upper part could be traced to the 305-m stack, which emits flue gases from combustion of low-sulfur coal. The lower part could be traced to two remaining sources, one of which is equipped with a wet limestone scrubber for flue gas desulfurization. A detailed analysis of the plume structure ruled out the possibility that the higher oxidation rate was associated with the scrubbed plume. The authors believe that the higher rate was a result of greater dispersion of the lower plume caused by a cross-wind shear and a mechanically-induced turbulence resulting from the special topography of the area and by a developing thermal boundary layer. Two edge-of-plume effects—maximum NO 2 concentration at the border of the plume and a high concentration of condensation nuclei in the vicinity of the plume-are also discussed.

Meagher, J. F.; Stockburger, L.; Bonanno, R. J.; Luria, M.

160

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

161

Greenhouse Gases  

NSDL National Science Digital Library

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

2012-08-03

162

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

163

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

PubMed

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

Xue, Dan; Yin, Jingyuan

2014-05-01

164

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

PubMed Central

The joint action of O3 and SO2 stress on plants was investigated by determining the quantitative relationship between air pollutant fluxes and effects on stomatal conductance. Gas exchange measurements of O3, SO2, and H2O vapor were made for Pisum sativum L. (garden pea). Plants were grown under controlled environments, and O3, SO2, and H2O vapor fluxes were evaluated with a whole-plant gas exchange chamber using the mass-balance approach. Maximum O3 and SO2 fluxes per unit area (2 sided) into leaves averaged 8 nanomoles per square meter per second with exposure to either O3 or SO2 at 0.1 microliters per liter. Internal fluxes of either O3 or SO2 were reduced by up to 50% during exposure to combined versus individual pollutants; the greatest reduction occurred with simultaneous versus sequential combinations of the pollutants. Stomatal conductance to H2O was substantially altered by the pollutant exposures, with O3 molecules twice as effective as SO2 molecules in inducing stomatal closure. Stomatal conductance was related to the integrated dose of pollutants. The regression equations relating integrated dose to stomatal conductance were similar with O3 alone, O3 plus added SO2, and O3 plus SO2 simultaneously; i.e. a dose of 100 micromoles per square meter produced a 39 to 45% reduction in conductance over nonexposed plants. With SO2 alone, or SO2 plus added O3, a dose of 100 micromoles per square meter produced a 20 to 25% reduction in conductance. When O3 was present at the start of the exposure, then stomatal response resembled that for O3 more than the response for SO2. This study indicated that stomatal responses with combinations of O3 and SO2 are not dependent solely on the integrated dose of pollutants, but suggests that a metabolic synergistic effect exists. PMID:16665041

Olszyk, David M.; Tingey, David T.

1986-01-01

165

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

E-print Network

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

Weston, Ken

166

Oxidation of CS2 and COS - sources for atmospheric SO2  

NASA Technical Reports Server (NTRS)

The oxidation of COS and CS2 by reaction with hydroxyl radicals is investigated as a possible source of atmospheric SO2 in remote marine regions. Calculations of the vertical profiles of SO2 were performed based on a one-dimensional photochemical model of the formation and destruction of SO2 by various processes for observed O3, CO, CH4 and H2O profiles at 15 deg S. Variations in the rate of SO2 destruction, the chosen deposition velocity and the loss due to aerosols are shown to lead to similar SO2 profiles, which indicate higher mixing ratios at high altitude, while the oxidation of dimethyl sulfide or hydrogen sulfide can not account for the profiles observed. Possible diffuse sources of CS2 and COS are indicated, and it is concluded that the oxidation of COS and possibly CS2 may provide an explanation for the existence of a uniform background level of SO2.

Logan, J. A.; Mcelroy, M. B.; Wofsy, S. C.; Prather, M. J.

1979-01-01

167

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

168

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

169

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

170

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

171

Abatement of particulate-laden SO 2 in tapered bubble column with internals  

Microsoft Academic Search

The performance of particulate-laden SO2 scrubbing in a modified tapered bubble column with internals is reported in this article. The presence of particles improved\\u000a the particulate-laden SO2 removal efficiency to about 15% that was elucidated by the facilitated adsorptive mass transport. Experimentation revealed\\u000a that nearly 100% removal efficiency of particulate-laden SO2 was achievable without any additives or pretreatment under certain

Amitava Bandyopadhyay

2009-01-01

172

The effect of wind velocity, air temperature and humidity on NH 3 and SO 2 transfer into bean leaves ( phaseolus vulgaris L.)  

NASA Astrophysics Data System (ADS)

The influence of wind velocity, air temperature and vapour pressure deficit of the air (VPD) on NH 3 and SO 2 transfer into bean leaves ( Phaseolus vulgaris L.) was examined using a leaf chamber. The measurements suggested a transition in the properties of the leaf boundary layer at a wind velocity of 0.3-0.4 ms -1 which corresponds to a Recrit value of about 2000. At higher wind velocities the leaf boundary layer resistance ( rb) was 1.5-2 times lower than can be calculated from the theory. Nevertheless, the assessed relationships between rb and wind velocity appeared to be similar to the theoretical derived relationship for rb. The NH 3 flux and in particular the SO 2 flux into the leaf strongly increased at a VPD decline. The increase of the NH 3 flux could be attributed to an increase of the stomatal conductance ( gs). However, the increase of the SO 2 flux could only partly be explained by an increase of gs. An apparent additional uptake was also observed for the NH 3 uptake at a low temperature and VPD. The SO 2 flux was also influenced by air temperature which could be explained by a temperature effect on gs. The results suggest that calculation of the NH 3 and SO 2 flux using data of gs gives a serious understimation of the real flux of these gases into leaves at a low temperature and VPD.

van Hove, L. W. A.; Vredenberg, W. J.; Adema, E. H.

173

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

174

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

EPA Science Inventory

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

175

A diarylethene as the SO2 gas generator upon UV irradiation.  

PubMed

A closed-ring isomer of a diarylethene having a sulfone group works as the reagent for SO2 gas generation with thermal stability even at 70 °C, and it rapidly reverts to the open-ring isomer and generates the SO2 gas to induce cell death upon UV irradiation. PMID:25519491

Kodama, Ryuhei; Sumaru, Kimio; Morishita, Kana; Kanamori, Toshiyuki; Hyodo, Kengo; Kamitanaka, Takashi; Morimoto, Masakazu; Yokojima, Satoshi; Nakamura, Shinichiro; Uchida, Kingo

2015-01-15

176

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

EPA Science Inventory

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

177

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

EPA Science Inventory

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

178

76 FR 79574 - Revisions to Final Response to Petition From New Jersey Regarding SO2  

Federal Register 2010, 2011, 2012, 2013, 2014

...to Final Response to Petition From New Jersey Regarding SO 2 Emissions From...the Final Response to Petition From New Jersey Regarding SO 2 Emissions From...standard (NAAQS) in the State of New Jersey, and not in specific counties...

2011-12-22

179

77 FR 26444 - Revisions to Final Response To Petition From New Jersey Regarding SO2  

Federal Register 2010, 2011, 2012, 2013, 2014

...to Final Response To Petition From New Jersey Regarding SO2 Emissions From the...Final Response to Petition From New Jersey Regarding SO 2 Emissions From...standard (NAAQS) in the State of New Jersey and remove the references to...

2012-05-04

180

76 FR 79541 - Revisions to Final Response to Petition From New Jersey Regarding SO2  

Federal Register 2010, 2011, 2012, 2013, 2014

...to Final Response to Petition From New Jersey Regarding SO2 Emissions From the...the Final Response to Petition From New Jersey Regarding SO2 Emissions From the...standard (NAAQS) in the State of New Jersey, and not in specific counties...

2011-12-22

181

40 CFR 97.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

182

40 CFR 96.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

183

40 CFR 97.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

184

40 CFR 96.254 - Compliance with CAIR SO2 emissions limitation.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

185

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

EPA Science Inventory

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

186

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

187

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

Federal Register 2010, 2011, 2012, 2013, 2014

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

2011-04-07

188

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

Microsoft Academic Search

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

Wenxiong Huang; Benjamin F. Hobbs

1994-01-01

189

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

EPA Science Inventory

The object of the study was to clarify the relationships among stomatal, residual, and epidermal conductances in determining the flux of SO2 air pollution to leaves. Variations in leaf SO2 and H2O vapor fluxes were determined using four plant species: Pisum sativum L. (garden pea...

190

Anthropogenic emissions of SO 2 and NO x in Asia: Emission inventories  

Microsoft Academic Search

The anthropogenic emissions of SO2 and NOx for 25 Asian countries east of Afghanistan and Pakistan have been calculated for 1975, 1980, 1985, 1986 and 1987 based on fuel consumption, sulfur content in fuels and emission factors for used fuels in each emission category. The provincial- and regional-based calculations have also been made for China and India. The total SO2

Nobuo Kato; Hajime Akimoto

2007-01-01

191

Satellite observation of SO2 from El Chichon - Identification and measurement  

NASA Technical Reports Server (NTRS)

Absorption bands between 300 nm and 315 nm were observed in spectral scans of the atmospheric albedo made by the solar backscattered ultraviolet instrument (SBUV) on Nimbus 7 following the eruption of El Chichon. It is shown that these bands coincide with peaks in the absorption coefficient spectrum of SO2 and use the magnitude of the absorption to estimate the column content of SO2 present. A maximum concentration of 15 matm-cm of SO2 was observed west of Hawaii on April 15; the minimum detectable amount of SO2 in a single scan is about 1 matm-cm. The disappearance of the band structure at wavelengths below 300 nm indicates that the SO2 was between 20 km and 30 km altitude. An excess albedo was also observed near 300 nm which was attributed to increased scattering from volcanic aerosols; the wavelength of the scattering feature indicates that the aerosols also were near 25 km altitude.

Mcpeters, R. D.; Heath, D. F.; Schlesinger, B. M.

1984-01-01

192

SO2 frost - UV-visible reflectivity and Io surface coverage  

NASA Technical Reports Server (NTRS)

The reflectance spectrum in the range 0.24-0.85 microns of SO2 frost is measured in light of the discovery of SO2 gas in the atmosphere of Io and the possible discovery of the frost on its surface. Frost deposits up to 1.5 mm thick were grown in vacuum at 130 K and bi-directional reflectance spectra were obtained. Typical SO2 frost is found to exhibit very low reflectivity (2-5%) at 0.30 microns, rising steeply at 0.32 microns to attain a maximum reflectivity (75-80%) at 4.0 microns and uniformly high reflectivity throughout the visible and near infrared. Comparison with the full disk spectrum of Io reveals that no more than 20% of the surface can be covered with optically thick SO2 frost. Combinations of surface materials including SO2 frost which can produce the observed spectrum are indicated.

Nash, D. B.; Fanale, F. P.; Nelson, R. M.

1980-01-01

193

Distribution of H2O and SO2 in the atmosphere of Venus  

NASA Astrophysics Data System (ADS)

The large variability of H2O and SO2in the atmosphere of Venus above the cloud tops is puzzling, especially since there is little evidence for their variability in the lower atmosphere. We note three important related facts: (1) The abundances of H2O and SO2in the deep atmosphere are of the same order of magnitude ~100 ppmv, (2) there is a rapid decrease in H2O and SO2 just above the cloud tops, resulting in sharp vertical gradients in their vertical profiles, and (3) the primary removal mechanism for H2O and SO2above the cloud tops is formation of H2SO4 aerosols. In this work we examine the possibility that H2O and SO2could mutually regulate each other in 1-D and 2-D models.

Yung, Y. L.; Liang, M.; Parkinson, C. D.

2009-12-01

194

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

Microsoft Academic Search

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

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

2005-01-01

195

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

E-print Network

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

Rocca, Jorge J.

196

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

197

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

198

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

199

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

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

200

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

NASA Astrophysics Data System (ADS)

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 orders of magnitude. The reaction with alternate high and low rate constants enhances monthly mean wintertime sulfate by 4-20% and 0.4-1.2% respectively. The reaction does not significantly impact summertime sulfate. The higher sulfate predictions in winter compare better with the observed data as the model tends to underpredict sulfate concentrations both in winter and summer. We also investigate the potential impact of the gas-phase oxidation of sulfur dioxide by the Stabilized Criegee Intermediate (SCI) using a recently measured rate constant for its reaction with sulfur dioxide. Model results indicate that the gas-phase oxidation of sulfur dioxide by the SCI does not significantly affect sulfate concentrations due to the competing reaction of the SCI with water vapor. The current estimate of the rate constant for the SCI reaction with water vapor is too high for the SCI reaction with sulfur dioxide to significantly affect sulfate production. However, a sensitivity analysis using a lower rate constant for the water vapor reaction suggests that the SCI reaction with sulfur dioxide could potentially enhance sulfate production in the model. Further study is needed to accurately measure the rate constants of the aqueous-phase oxidation of S(IV) by nitrogen dioxide and the gas-phase reaction of the SCI with water vapor.

Sarwar, Golam; Fahey, Kathleen; Kwok, Roger; Gilliam, Robert C.; Roselle, Shawn J.; Mathur, Rohit; Xue, Jian; Yu, Jianzhen; Carter, William P. L.

2013-04-01

201

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

PubMed

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

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

2015-03-01

202

Measurements of dimethyl sulfide and SO2 during GTE/CITE 3  

NASA Technical Reports Server (NTRS)

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

Ferek, Ronald J.; Hegg, Dean A.

1993-01-01

203

Emission of SO2, CO2, and H2S from Augustine Volcano, 2002-2008  

USGS Publications Warehouse

Airborne surveillance of gas emissions from Augustine Volcano and other Cook Inlet volcanoes began in 1990 to identify baseline emission levels during noneruptive conditions. Gas measurements at Augustine for SO2, CO2, and H2S showed essentially no evidence of anomalous degassing through spring 2005. Neither did a measurement on May 10, 2005, right after the onset of low level seismicity and inflation. The following measurement, on December 20, 2005, showed Augustine to be degassing about 600 metric tons per day (t/d) of SO2, and by January 4, 2006, only 7 days before the first explosive event, SO2 emissions had climbed to ten times that amount. Maximum emission rates measured during the subsequent eruption were: 8,930 t/d SO2 (February 24, 2006), 1,800 t/d CO2 (March 9, 2006), and 4.3 t/d H2S (January 19, 2006). In total, 45 measurements for SO2 were made from December 2005 through the end of 2008, with 19 each for CO2 and H2S during the same period. Molar CO2/SO2 ratios averaged about 1.6. In general, SO2 emissions appeared to increase during inflation of the volcanic edifice, whereas CO2 emissions were at their highest during the period of deflation associated with the vigorous effusive phase of the eruption in March. High SO2 was probably associated with degassing of shallow magma, whereas high CO2 likely reflected deep (>4 km) magma recharge of the sub-volcanic plumbing system, For the 2005-6 period, the volcano released a total of about 1.5 x 106 tons of CO2 to the atmosphere, a level similar to the annual output of a medium-sized natural-gas-fired powerplant. Augustine also emitted about 8 x 105 tons of SO2, similar to that produced by the 1976 and 1986 eruptions of the volcano.

McGee, Kenneth A.; Doukas, Michael P.; McGimsey, Robert G.; Neal, Christina A.; Wessels, Rick L.

2010-01-01

204

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

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

205

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

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

206

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

PubMed

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

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

2002-05-01

207

Air-to-sea flux of soluble iron: is it driven more by HNO3 or SO2? - an examination in the light of dust aging  

NASA Astrophysics Data System (ADS)

Aeolian dust provides the major micronutrient of soluble Fe to organisms in certain regions of the global ocean. In this study, we conduct numerical experiments using the MOZART-2 atmospheric chemistry transport model to simulate the global distribution of soluble Fe flux and Fe solubility. One of the mechanisms behind the hypothesis of acid mobilization of Fe in the atmosphere is that the coating of acidic gases changes dust from hydrophobic to hydrophilic, a prerequisite of Fe mobilization. We therefore include HNO3, SO2 and sulfate (SO42-) as dust transformation agents in the model. General agreement in Fe solubility within a factor of 2 is achieved between model and observations. The total flux of soluble Fe to the world ocean is estimated to be 731-924×109 g yr-1, and the average Fe solubility is 6.4-8.0%. Wet deposition contributes over 80% to total soluble Fe flux to most of the world oceans. Special attention is paid to the relative role of HNO3 versus SO2 and sulfate. We demonstrate that coating by HNO3 produces over 36% of soluble Fe fluxes compared to that by SO2 and sulfate combined in every major oceanic basin. Given present trends in the emissions of NOx and SO2, the relative contribution of HNO3 to Fe mobilization may get even larger in the future.

Yang, H.; Gao, Y.

2007-07-01

208

Separation of polar gases from nonpolar gases  

Microsoft Academic Search

Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol

S. Kulprathipanja; S. S. Kulkarni

1986-01-01

209

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

E-print Network

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

Schmalensee, Richard

210

FACTORS AFFECTING DRY DEPOSITION OF SO2 ON FORESTS AND GRASSLANDS  

EPA Science Inventory

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

211

Mercury, NOx, SO2, and O3 from power plants in the Southeastern U.S. during NOMADSS  

NASA Astrophysics Data System (ADS)

The NOMADSS experiment (Nitrogen, Oxidants, Mercury and Aerosols: Deposition, Sources and Sinks) was carried out using the NSF/NCAR C-130 research aircraft during June and July, 2013. The aircraft was outfitted with an extensive suite of instrumentation for mercury (Hg), ozone (O3), nitrogen oxides (NO + NO2), hydrogen oxide radicals (HOx = OH + HO2), nitrous acid (HONO), sulfur dioxide (SO2), sulfuric acid (H2SO4), carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds (VOCs), aerosols, and other tracers. A primary goal of the experiment was to quantify the Hg emissions from large coal-fired power plants in the Southeastern U.S. We performed flybys in the continental boundary layer of approximately 10 different power plants during the experiment and observed a wide range in both absolute concentrations and relative enhancements of Hg compared with co-emitted pollutants. In the U.S., the power generation sector is a major source of anthropogenic Hg emissions. Power plant Hg emissions have not been regulated until recently, though some emissions reductions have been achieved historically as a co-benefit of regulations on SO2 and aerosols. New rules on power plant emissions of Hg and other pollutants went into force in December, 2011. Coal-fired power plants have until 2015 to comply with these rules by installing scrubbers for Hg. As a consequence of the phase-in of new Hg emissions control technologies, the power plant plumes we sampled during NOMADSS represent a broad distribution of controlled and uncontrolled emission sources. We observed a large range of plume enhancements in Hg, NOx and SO2 (referenced to CO and/or CO2). In at least one case, we identified significant O3 production in a relatively fresh plume. Using CO and CO2 as stable tracers, we can calculate the instantaneous emissions of Hg and other compounds for each source and compare to emissions inventories. We will also examine the photochemical processing of each power plant plume with respect to Hg, NOx, SO2/H2SO4, and O3.

Ambrose, J. L.; Jaffe, D. A.; Gratz, L.; Jaegle, L.; Selin, N. E.; Shah, V.; Giang, A.; Song, S.; Mauldin, L.; Cantrell, C. A.

2013-12-01

212

Inspection of non-CO2 greenhouse gases from emission sources and in ambient air by Fourier-transform-infrared-spectrometry: Measurements with FTIS-MAPS.  

PubMed

Infrared spectrometry is a versatile basis to analyse greenhouse gases in the atmosphere. A multicomponent air pollution software (MAPS) was developed for retrieval of gas concentrations from radiation emission as well as absorption measurements. Concentrations of CO, CH4, N2O, and H2O as well as CO2, NO, NO2, NH3, SO2, HCl, HCHO, and the temperature of warm gases are determined on-line. The analyses of greenhouse gases in gaseous emission sources and in ambient air are performed by a mobile remote sensing system using the double-pendulum interferometer K300 of the Munich company Kayser-Threde. Passive radiation measurements are performed to retrieve CO, N2O, and H2O as well as CO2, NO, SO2, and HCl concentrations in smoke stack effluents of thermal power plants and municipal incinerators and CO and H2O as well as CO2 and NO in exhausts of aircraft engines. Open-path radiation measurements are used to determine greenhouse gas concentrations at different ambient air conditions and greenhouse gas emission rates of diffusive sources as garbage deposits, open coal mining, stock farming together with additional compounds (e.g. NH3), and from road traffic together with HCHO. Some results of measurements are shown. A future task is the verification of emission cadastres by these inspection measurements. PMID:24213905

Schäfer, K; Haus, R; Heland, J

1994-05-01

213

Scanning tomography of SO2 distribution in a volcanic gas plume  

Microsoft Academic Search

Two-dimensional cross sections of the sulphur dioxide (SO2) distribution in the volcanic gas plume of Mt. Etna were reconstructed using tomographic techniques. The data for these projections were generated by a network of five automated scanning spectrometers, positioned on the flanks of the volcano. These measure slant-column amounts of SO2 at 105 different angles, every four minutes. Stable wind conditions

T. E. Wright; M. Burton; D. M. Pyle; T. Caltabiano

2008-01-01

214

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

215

Responses to sequential exposure to SO 2 and salinity in soybean ( Glycine max L.)  

Microsoft Academic Search

Soybean plants (Glycine max L. cv. Buchanan) were subjected to one of three levels of salinity preteatment (with electrical conductivities of 0.7, 4.4 and 6.5 dS m-1) and then exposed to one of three concentrations of SO2 (1, 145 and 300 bl l-1 for 5 h d-1), or vice versa. Each stress episode lasted 3 weeks. Both salinity and SO2

Ma Qifu; Frank Murray

1994-01-01

216

SO2Induced Enhancement of Inhalative Allergic Sensitization Inhibition by Anti-Inflammatory Treatment  

Microsoft Academic Search

Epidemiological studies have shown a relationship between air pollution and allergic airway disease. In a previous study we have found that exposure to SO2 enhances allergic sensitization to inhaled ovalbumin (OA) in the guinea pig. We have now investigated the influence of pre-treatment with anti-inflammatory drugs on SO2-induced enhancement of allergic sensitization in this model. Four groups of 6 guinea

F. Riedel; S. Naujukat; J. Rüschoff; S. Petzoldt; C. H. L. Rieger

1992-01-01

217

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

PubMed

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

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

2014-11-01

218

Photodissociation of SO2 as a way to cold atoms and molecules  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

219

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

2005-05-01

220

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

PubMed

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

Xu, Yuan

2011-01-15

221

Effects of SO2 on Stomatal Metabolism in Pisum sativum L. 1  

PubMed Central

Pea (Pisum sativum L. cv `Little Marvel') plants were exposed to SO2 for short term (3 hours) and long term (2 days) at 0.2 and at 0.5 microliter per liter (ppm) levels. The effect of this treatment on the activity of phosphoenolpyruvate carboxylase, NAD- and NADP-malate dehydrogenases, and alanine aminotransferase from epidermis and whole leaves was investigated. Short-term exposure to SO2 at 0.2 or 0.5 ppm decreased the activity of the carboxylase and the dehydrogenases in the epidermis. In contrast, the activity of the same three enzymes increased in whole leaves with either short- or long-term exposure to SO2. Alanine aminotransferase in epidermis or whole leaves was not much affected by short-term exposure, but the epidermal activity was decreased and whole leaf activity was increased with long-term exposure. SO2 exposure which was initiated prior to illumination decreased the free thiol content of both epidermis and of whole leaf. Net photosynthesis was reversibly inhibited by long-term exposure to SO2 at 0.5 ppm. No effect of 0.5 ppm SO2 on stomatal conductance was detectable after 3 hours. Stomatal conductance appeared to decrease after longer exposure times (2 days) at 0.5 ppm. PMID:16663045

Rao, I. Madhusudana; Amundson, Robert G.; Alscher-Herman, Ruth; Anderson, Louise E.

1983-01-01

222

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

223

Reversible uptake of COS, CS2, and SO2: ionic liquids with O-alkylxanthate, O-alkylthiocarbonyl, and O-alkylsulfite anions.  

PubMed

CO(2)-binding organic liquids (CO(2)BOLs) are mixtures of a base (typically an amidine or guanidine) and an alcohol, and have been shown to reversibly capture and release CO(2) with low reaction energies and high gravimetric CO(2) capacity. We now report the ability of such liquid blends to chemically bind and release other acid gases such as CS(2), COS, and SO(2) analogously to CO(2). These systems bind with sulfur-containing acid gases to form colored ionic liquids with new O-alkylxanthate, O-alkylthiocarbonyl, and O-alkylsulfite anions. The capture and thermal stripping of each acid gas from these systems and their applicability towards flue gas desulfurization is discussed. PMID:19551772

Heldebrant, David J; Yonker, Clement R; Jessop, Philip G; Phan, Lam

2009-08-01

224

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

USGS Publications Warehouse

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

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

2013-01-01

225

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

226

Contributions of anthropogenic and natural sources of sulfur to SO2, H2SO4(g) and nanoparticle formation  

NASA Astrophysics Data System (ADS)

Atmospheric nanoparticles (NPs) are important intermediates in the transition from gas-phase molecules to new aerosols that can activate into cloud droplets. Through increases in the emissions of sulfur-containing gases, human activities have likely increased the number of NPs produced in the atmosphere. To have significant impacts, however, sulfur pollution must be transported away from the surface, where NP formation is inefficient, to higher altitudes. To characterize this anthropogenic influence, tagged tracers are implemented in a global atmospheric transport model. The tagged tracers are used to track the contributions of sulfur from five sources (anthropogenic, oceanic, volcanic, aircraft, and stratospheric) to the gas-phase burdens of SO2 and H2SO4(g), and the rates of forming atmospheric NPs. Because NPs may be produced by a variety of mechanisms, three different aerosol nucleation schemes (binary, ternary and ion-induced) are used in the model calculations. Of the SO2 in the global troposphere, the tagged tracers indicate that about 69% originates from anthropogenic surface emissions, 20% from the oceans and 10% from de-gassing volcanoes. The same sources contribute about 56%, 24% and 19%, respectively, to the global tropospheric H2SO4(g) burden. The anthropogenic contribution for H2SO4(g) is reduced because anthropogenic SO2 produces H2SO4(g) less efficiently than oceanic and volcanic sulfur. Regardless of the underlying nucleation assumptions, the simulations show a pronounced influence of anthropogenic sulfur on atmospheric NP formation, particularly in the Northern Hemisphere. Utilizing the tagged H2SO4(g) contributions, anthropogenic sulfur is estimated to account for roughly 69% of the NP formation in the Northern Hemisphere, 31% in the Southern Hemisphere and 56% across the global troposphere. In the key region of the upper troposphere, anthropogenic and oceanic sulfur both make sizeable contributions to NP formation (54% and 37%, respectively). The tagged tracer contributions suggest that human activities have probably more than doubled the NP production rate in the atmosphere from preindustrial to modern times.

Lucas, D. D.; Akimoto, H.

2007-06-01

227

Thermodynamic models of the chemistry of lunar volcanic gases  

NASA Technical Reports Server (NTRS)

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

Fegley, Bruce, Jr.

1991-01-01

228

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

229

SO2 noontime-peak phenomenon in the North China Plain  

NASA Astrophysics Data System (ADS)

A phenomenon of frequent noontime SO2 concentration peaks was discovered in a detailed analysis of the SO2 concentrations in the North China Plain (NCP). The possible causes and their contributions are analyzed. The impacts of such a phenomenon on the sulphur cycle were studied and the implications of the phenomenon for atmospheric chemistry, cloud physics, and climate were discussed. Different from the more common SO2 diurnal patterns with high nighttime concentrations, NCP witnessed high frequencies of noontime SO2 peaks, with an occurrence frequency of 50 to 72% at four stations. Down mixing of elevated pollution layers, plume transport processes, mountain-valley winds, and fog/high RH haze events were the possible causes. The contribution of each process varies from day to day and from station to station, however, none of those four processes can be neglected. SO2 peaks occurring during noontime instead of nighttime will lead to a 13 to 35% increase in sulphur dry deposition, a 9 to 23% increase in gas phase oxidation, and an 8 to 33% increase in aqueous phase conversions, which will increase the hygroscopicity and the light scattering of aerosols, thus having important impacts on atmospheric chemistry, cloud physics, and climate.

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

2014-08-01

230

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; Österlund, Lars; Ahuja, Rajeev

2013-09-11

231

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

232

Accurate predictions of C-SO2R bond dissociation enthalpies using density functional theory methods.  

PubMed

The dissociation of the C-SO2R bond is frequently involved in organic and bio-organic reactions, and the C-SO2R bond dissociation enthalpies (BDEs) are potentially important for understanding the related mechanisms. The primary goal of the present study is to provide a reliable calculation method to predict the different C-SO2R bond dissociation enthalpies (BDEs). Comparing the accuracies of 13 different density functional theory (DFT) methods (such as B3LYP, TPSS, and M05 etc.), and different basis sets (such as 6-31G(d) and 6-311++G(2df,2p)), we found that M06-2X/6-31G(d) gives the best performance in reproducing the various C-S BDEs (and especially the C-SO2R BDEs). As an example for understanding the mechanisms with the aid of C-SO2R BDEs, some primary mechanistic studies were carried out on the chemoselective coupling (in the presence of a Cu-catalyst) or desulfinative coupling reactions (in the presence of a Pd-catalyst) between sulfinic acid salts and boryl/sulfinic acid salts. PMID:25170742

Yu, Hai-Zhu; Fu, Fang; Zhang, Liang; Fu, Yao; Dang, Zhi-Min; Shi, Jing

2014-10-14

233

High solubility of SO2: evidence in an intensive fog event measured in the NCP region, China  

NASA Astrophysics Data System (ADS)

A field experiment was conducted in a heavy SO2 pollution area located in north China plain (NCP). During the experiment, SO2 and other air pollutants, liquid water content (LWC) of fog droplets, and basic meteorological parameters were measured. During the experiment, an intensive fog event occurred between 5 and 8 November 2009. During the fog period, the concentrations of SO2 showed a strong variability, and the variability was closely correlated to the appearances of fogs and LWC. For example, the averaged concentration of SO2 during the non-fog period was about 25 ppbv. By contrast, during the fog period, the concentration of SO2 reduced to about 4-7 ppbv. The large reduction of SO2 suggests that a majority of SO2 (about 70-80%) had been converted from gas-phase to aqueous-phase, showing a high solubility of SO2. However, according to the value of Henry Law constant, the solubility of SO2 is modest, which cannot explain the measured large reduction of SO2. This study highlights that the aqueous reactions of SO2 in the droplets of fogs play important roles to enhance the solubility of SO2. To account for the effect of aqueous reactions on the solubility of SO2, an "effective" Henry Law constant of SO2 is proposed in this study. The study shows that without considering aqueous reactions of SO2 in fog droplets, the estimate of the partitioning of SO2 in droplets is significantly lower than the measured values. By contrast, when the "effective" Henry Law constant is applied in the calculation, the calculated SO2 concentrations are significantly improved, showing that the aqueous reactions of SO2 play important roles in controlling the solubility of SO2, and should be considered in model calculations.

Zhang, Q.; Tie, X.

2011-01-01

234

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

NASA Astrophysics Data System (ADS)

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

Sachan, Himanshu; Sarkar, Chinmoy; Sinha, Baerbel

2013-04-01

235

Pretreatment of wheat straw using SO2 dissolved in hot water.  

PubMed

Efficient pretreatment is important for complete enzymatic conversion of lignocellulosic materials. Pretreatment of wheat straw with sulfur dioxide (SO(2)) dissolved in hot water achieved xylose and total product yields of up to 61.1% and 93.9%, respectively, based on the mass of lignocellulose in wheat straw. The apparent activation energies for hemicellulose conversion and xylose dehydration were 7.8 and 9.0 kJ/mol. FT-IR spectra of the residual solid after treatment showed that the hemicellulosic components were converted, the hydrogen bonds in cellulose were broken, but the lignin structure was not changed. Importantly, the SO(2) was recovered from the product mixture by steam stripping and could be reused. Thus, the SO(2)-H(2)O system is an efficient and environmentally friendly way for the conversion of hemicellulose in wheat straw into monosaccharides, such as xylose, glucose and arabinose. PMID:22989658

Liu, Weina; Hou, Yucui; Wu, Weize; Niu, Muge; Wang, Wenhua

2012-11-01

236

Abatement of particulate-laden SO(2) in tapered bubble column with internals.  

PubMed

The performance of particulate-laden SO(2) scrubbing in a modified tapered bubble column with internals is reported in this article. The presence of particles improved the particulate-laden SO(2) removal efficiency to about 15% that was elucidated by the facilitated adsorptive mass transport. Experimentation revealed that nearly 100% removal efficiency of particulate-laden SO(2) was achievable without any additives or pretreatment under certain operating condition of the scrubber. An empirical correlation was developed to predict the performance of the modified tapered scrubber. Experimental values fitted excellently well with the predicted values through the correlation (within +/-5% deviation). The performance of the modified tapered bubble scrubber with column internals has been found to be better than a tapered bubble column without any internals. PMID:19890465

Bandyopadhyay, Amitava

2009-09-01

237

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

PubMed Central

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

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

2010-01-01

238

Sulfur species in volcanic gases.  

PubMed

A new analytical method for the determination of the sulfur species (SO2, H2S, S8(0)) in volcanic gases is proposed by revising, updating, and improving previous methods. The most significant advantages of the proposed procedure can briefly be summarized, as follows: (i) the reaction among sulfur species stops during the gas sampling by using preevacuated thorion-tapped vials with purified 0.15M Cd(OH)2 in 4 M NaOH to favor the precipitation of H2S as CdS; (ii) all the sulfur species (SO2, H2S, S8(0)) are analyzed by ion chromatography, after conversion to SO4, which allows the detection limit to be lowered significantly with respect to the previous studies; (iii) appropriate aliquots from intermediate steps may be used to determine other species commonly present in volcanic gases such as CO2, HCI, HF, HBr, HI, and so forth; (iv) determination of all the other gas species is not jeopardized by the proposed method, i.e., one single vial can be used for analyzing the full chemical composition of a volcanic gas with the exception of NH3. Statistical parameters calculated from gas sampling data at the F5 crater fumarole in Vulcano Island (Aeolian Islands, southern Italy), suggest that the standard error of mean (s/ root n) is higher for S (0.10), followed by SO2, H2S, and CO2 (0.04, 0.038, and 0.028, respectively). SO2 shows the higher variation coefficient (12.1%) followed by H2S, S, and CO2 (5.7, 1.5, and 0.8%, respectively). Furthermore, if the time dependence of sampling is taken into account, the measured values, instead of fluctuating in a random manner, tend to follow systematic patterns, out of statistical control, possibly suggesting a sort of natural fluctuation of the volcanic system. Other crater fumaroles from volcanic systems located in different geodynamical areas (Hawaii, USA, El Chichon, Mexico, Poas, Costa Rica) have been analyzed as well. PMID:11510838

Montegrossi, G; Tassi, F; Vaselli, O; Buccianti, A; Garofalo, K

2001-08-01

239

Effects of reducing SO2 and NOx emission from ships on air quality in Alaska  

NASA Astrophysics Data System (ADS)

We performed simulations with the Alaska-adapted WRF/Chem using the same meteorological conditions of January 2000, but alternatively applying the emissions of 2000 (REF), emissions of 2000 with the ship-emission reductions for the planned North American Emission Contral Area (ECA) for SO2 only (ECA1) and SO2 and NOx (ECA2) that have been proposed by the International Maritime Organization for 2015. The analysis focused on the air quality along the international shipping lanes (ISL), in the ECA and over Alaska (AK). Our goal is to examine how the decreases in ship emissions in the ISL and ECA affect to air quality in Alaska. Our model results show that reducing SO2 and NOx ship-emissions reduces the concentration of sulfur and nitrogen compounds over Alaska despite of no changes in Alaska emissions. The reductions of pollutants over the ISL, ECA and AK stemming from concurrent SO2-NOx ship emission reductions are an order of magnitude of those stemming from SO2 reduction in ship emissions only. Reductions in sulfur compounds reach up to 14km while reductions of nitrogen compounds reach to only about 7km. Reductions of sulfate and nitrate in clouds are highest at the top of the boundary layer. Among the three regions of interest, strongest reductions occur over the ECA and ISL for sulfur and nitrogen compounds, respectively, since the ECA (ISL) has highest reductions of SO2 (NOx). The PM2.5 speciation partitioning over all three regions marginally changes when the ship emissions change. Sulfate is the major component of PM2.5 in all regions. Closer to the land, organic carbon (OC) partitioning is higher indicating the enhancing impacts of inland anthropogenic emissions to total PM2.5 concentrations over land.

Tran, T. T.; Mölders, N.

2011-12-01

240

H(2) production through electro-oxidation of SO(2): identifying the fundamental limitations.  

PubMed

Sulphur dioxide (SO2), a known industrial pollutant and pulmonary irritant, is emitted to the atmosphere in excess of 120 Mt per annum. Great strides have been taken to reduce SO2 emissions, but with the growth of specifically China, and to a lesser extent India, it is on the rise again. The electrolysis of aqueous solutions of dissolved SO2 holds huge environmental potential in that SO2 is converted to sulphuric acid (H2SO4) and at the same time hydrogen gas is produced. A further benefit or incentive is that a sulphur depolarised electrolyser (SDE) operates at an applied potential that is about one volt lower than that of a regular water electrolyser. In taking this technology forward the greatest improvement to be made is in developing a suitable electrocatalyst, which is also the 'lowest hanging fruit' in that very limited research and development has been conducted on the electrocatalyst for this process. In this work, density functional theory is employed to model the electro-oxidation of SO2 on single crystal planes of the 4d and 5d transition metals. Two reaction mechanisms are considered, a HSO3 intermediate pathway and a SO3 intermediate pathway. The binding energies of all intermediates are found to scale with the surface reactivity (measured as the adsorption of OH). Irrespective of the pathway water needs to be activated and reduction of SO2 to elemental sulphur must be avoided. This requirement alone calls for an electrode potential of at least 0.7-0.8 V for all the investigated transition metals and thus challenges the proclaimed goal to operate the SDE at 0.6 V. A high chemical barrier is further found to severely limit the oxidation reaction on reactive metals. A much higher catalytic activity can be obtained on precious metals but at the cost of running the reaction at high overpotentials. PMID:24728561

Kriek, Roelof J; Rossmeisl, Jan; Siahrostami, Samira; Björketun, Mårten E

2014-05-28

241

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

242

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

243

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

244

CONCENTRATION STATISTICS BY WIND DIRECTION FOR 1976 ST. LOUIS SO2 MEASUREMENTS AND MODEL ESTIMATES  

EPA Science Inventory

In a previous evaluation of the urban air quality simulation model RAM using hourly SO2 concentrations measured in 1976 at 13 sites during the Regional Air Pollution Study conducted in St. Louis, Missouri, bias with stability was noted. A speculated cause of maxima from the model...

245

SORBENT/UREA SLURRY INJECTION FOR SIMULTANEOUS SO2/NOX REMOVAL  

EPA Science Inventory

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

246

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...

247

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...

248

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

249

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 ...

250

PROCEEDINGS: FIRST COMBINED FGD AND DRY SO2 CONTROL SYMPOSIUM. VOLUME 2. SESSIONS 5 AND 6  

EPA Science Inventory

The proceedings document presentations at the First Combined FGD and Dry SO2 Control Symposium, in St. Louis, MO, October 25-28, 1988. The symposium, jointly sponsored by EPA and EPRI, had as its objective the exchange of technical and regulatory information on sulfur oxide contr...

251

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...

252

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 ...

253

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 3. SESSIONS 5B, 6A, AND 6B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

254

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 4. SESSIONS 7, 8A, AND 8B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

255

EVALUATION OF SORBENTS AND ADDITIVES FOR DRY SO2 (SULFUR DIOXIDE) REMOVAL  

EPA Science Inventory

The paper gives results of bench-scale reactivity studies of alkaline sorbents, performed in an integrated fixed-bed reactor, simulating the fabric filter dust layer of dry flue gas desulfurization (FGD) systems. Relative humidity significantly affected SO2 absorption by lime and...

256

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...

257

EVALUATION OF SORBENTS AND ADDITIVES FOR DRY SO2 (SULFUR DIOXIDE) REMOVAL (JOURNAL VERSION)  

EPA Science Inventory

The paper gives results of bench-scale reactivity studies of alkaline sorbents, performed in an integrated fixed-bed reactor, simulating the fabric filter dust layer of dry flue gas desulfurization (FGD) systems. Relative humidity significantly affected SO2 absorption by lime and...

258

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 2. SESSIONS 4A, 4B, AND 5A  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

259

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...

260

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 ...

261

PROCEEDINGS: 1993 SO2 CONTROL SYMPOSIUM - VOLUME 1. SESSIONS 1, 2, 3A, AND 3B  

EPA Science Inventory

The report documents more than 100 presentations at the 1993 SO2 Control Symposium in Boston, MA, August 24-27, 1993. The presentations covered a wide range of topics: industry's strategies for dealing with Clean Air Act Amendments of 1990, including Phase I strategies, the emiss...

262

PROCEEDINGS: FIRST COMBINED FGD AND DRY SO2 CONTROL SYMPOSIUM. VOLUME 3. SESSIONS 7 AND 8  

EPA Science Inventory

The proceedings document presentations at the First Combined FGD and Dry SO2 Control Symposium, in St. Louis, MO, October 25-28, 1988. The symposium, jointly sponsored by EPA and EPRI, had as its objective the exchange of technical and regulatory information on sulfur oxide contr...

263

Performance Model of the Fluidized Bed Copper Oxide Process for SO2/NOx Control  

E-print Network

byproduct, in contrast to the sludge produced by conventional flue gas desulfurization (FGD) systems.4 technology for controlling SO2 and NOx emissions from coal-fired power plants. The development circulate between an absorber and regenerator. In the absorber, this sorbent is fluidized by the flue gas

Frey, H. Christopher

264

Study on Utilization Ratio of SO2 Sorbents in Semidry Flue Gas Desulfurization Technology  

Microsoft Academic Search

From the angle of chemical compositions of the desulfurization products, the utilization ratio of SO2 sorbents in semidry flue gas desulfurzation (FGD) technology was discussed in this study. Five desulfuzation residue samples, which were got from the semidry FGD devices of five different power plants, were analyzed about the chemical compostions. It was found that CaCO3 took up a big

Wang Wenlong; Xu Xiren; Ren Li; Dong Yong; Ma Chunyuan

2009-01-01

265

ALARM-LEVEL MONITOR FOR SO2 EMISSIONS FROM STATIONARY SOURCES  

EPA Science Inventory

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

266

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...

267

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...

268

Laboratory detection of protonated SO2 in two isomeric forms Valerio Lattanzi,1,a  

E-print Network

's atmosphere, and as a precursor in the industrial production of sulfuric acid. Since its detection in 1975 Ref­Pérot Fourier transform microwave spectroscopy, the rotational spectrum of protonated sulfur dioxide in two, and precise rotational constants have been derived. Because sulfur dioxide, SO2, is a widespread and very

Thorwirth, Sven

269

REACTIVITY STUDY OF SO2 CONTROL WITH ATMOSPHERIC AND PRESSURE HYDRATED SORBENTS  

EPA Science Inventory

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

270

SULU ORTAMDA SO2 GAZI LE FOSFAT KAYASINDAK KALS T N ÇÖZÜNME K NET  

Microsoft Academic Search

In this study, the dissolution kinetics of the calcite minerals of phosphate rock with SO2 gas in aqueous media were investigated. The effect of reaction temperature, solid-to-liquid ratio, particle size and stirring speed on the dissolution process was determined. It was observed that the dissolution of calcite minerals increased with increasing reaction temperature and stirring speed and with decreasing particle

Ahmet YARTA; Yüksel ABALI; Hakan TEMUR

271

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...

272

Complexes containing CO2 and SO2. Mixed dimers, trimers and tetramers.  

PubMed

Mixed dimers, trimers and tetramers composed of SO2 and CO2 molecules are examined by ab initio calculations to identify all minimum energy structures. While AIM formalism leads to the idea of a pair of C···O bonds in the most stable heterodimer, bound by some 2 kcal mol(-1), NBO analysis describes the bonding in terms of charge transfer from O lone pairs of SO2 to the CO ?* antibonding orbitals. The second minimum on the surface, just slightly less stable, is described by AIM as containing a single O···O chalcogen bond. The NBO picture is that of two transfers in opposite directions: one from a SO2 O lone pair to a ?* antibond of CO2, supplemented by CO2 Olp ? ?*(SO). Decomposition of the interaction energies points to electrostatic attraction and dispersion as the dominant attractive components, in roughly equal measure. The various heterotrimers and tetramers generally retain the dimer structure as a starting point. Cyclic oligomers are favored over linear geometries, with a preference for complexes containing larger numbers of SO2 molecules. PMID:24480872

Azofra, Luis Miguel; Scheiner, Steve

2014-03-21

273

CO2-SO2 clathrate hydrate formation on early Mars1 Eric Chassefirea,b  

E-print Network

formation is an observational fact for the current atmosphere of Earth. On early Mars, the60 cooling effect of sulfate aerosols would also have counteracted efficiently the warming effect61 due to SO2 greenhouse atmosphere was necessary in order to keep28 early Mars warm and wet. However, current models have not been

Boyer, Edmond

274

ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS  

EPA Science Inventory

Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

275

CO2 greenhouse in the early martian atmosphere: SO2 inhibits condensation  

NASA Technical Reports Server (NTRS)

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

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

1997-01-01

276

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

E-print Network

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

Spencer, John

277

PERFORMANCE EVALUATION OF AN INDUSTRIAL SPRAY DRYER FOR SO2 CONTROL  

EPA Science Inventory

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

278

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...

279

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

EPA Science Inventory

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

280

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

EPA Science Inventory

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

281

The Different Impacts of SO2 and SO3 on Cu/Zeolite SCR Catalysts  

SciTech Connect

The different impacts of SO2 and SO3 on Cu/zeolite SCR catalysts were investigated by SCR performance tests and multiple characterization techniques including temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS). The results indicate that a larger amount of highly dispersed CuSO4 formed in the zeolite catalysts (Z-CuSO4) upon SO3 poisoning, explaining the much more significant deactivation of the Cu/zeolite catalysts that were exposed to SO3 compared to poisoning by SO2. This paper provides the first demonstration that active sites of Cu/zeolite SCR catalysts involved in the storage and removal of sulfur can react with SO2 and SO3 in very different ways. In particular, the significant differences in the extent of sulfur uptake account for the considerably different impacts of SO2 and SO3 poisoning on the performance of Cu/zeolite SCR catalysts.

Cheng, Yisun; Lambert, Christine; Kim, Do Heui; Kwak, Ja Hun; Cho, Sung June; Peden, Charles HF

2010-06-19

282

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

NASA Technical Reports Server (NTRS)

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

Srivastava, Santosh K.; Nguyen, Hung P.

1987-01-01

283

Laboratory Measurements of SO2 and N2 Absorption Spectra for Planetary Atmospheres  

NASA Technical Reports Server (NTRS)

This laboratory project focuses on the following topics: 1) Measurement of SO2 ultraviolet absorption cross sections; and 2) N2 band and Line Oscillator Strengths and Line Widths in the 80 to 100 nm region. Accomplishments for these projects are summarized.

Stark, Glenn

2003-01-01

284

Flue gas SO 2/NO x control by combination of dry scrubber and electron beam  

NASA Astrophysics Data System (ADS)

This study examines the feasibility of adding an electron beam between the spray dryer and the fabric filter of "dry scrubber" flue gas desulfurization (FGD) systems. The beam promises effective removal of nitrogen oxides (NO x) and sulfur dioxide (SO 2), even at higher coal-sulfur levels than usually economic for dry scrubbers. The beam excites gas molecules, promoting reactions that convert SO 2 and NO x to acids that then react with calcium compounds and are removed by the filter. The cost findings are promising for both manufacture and operation. The system uses commercially available components. The relatively low temperatures and high humidity downstream of the spray dryer favor economic beam operation. The beam removes SO 2, so the dryer can be run for economy, not high removal. Pilot scale tests will soon be carried out which are designed to verify earlier bench scale test results and to serve as the next step to full commercialization. It is expected that better than 90% SO 2 and NO x removal will be achieved.

Helfritch, D. J.; Feldman, P. L.

285

ASSESSMENT OF SO2 AND NOX EMISSION CONTROL TECHNOLOGY IN EUROPE  

EPA Science Inventory

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

286

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...

287

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

E-print Network

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

Ford, Andrew

288

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...

289

AEROSOL FORMATION FROM DIESEL EXHAUST AND SO2. A CHAMBER STUDY  

EPA Science Inventory

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

290

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

291

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

EPA Science Inventory

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

292

INFLUENCE OF COAL MINERAL MATTER ON THE EFFECTIVENESS OF DRY SORBENT INJECTION FOR SO2 CONTROL  

EPA Science Inventory

The report describes the use of laboratory-, bench-, and pilot-scale facilities to examine the impact of mineral matter on calcium-based sorbent reactivity toward SO2. Two areas of concern were investigated: (1) deleterious effects of coal ash; and, (2) beneficial (promoter) effe...

293

FUNDAMENTAL PROCESSES INVOLVED IN SO2 CAPTURE BY CALCIUM-BASED ADSORBENTS  

EPA Science Inventory

The paper discusses the fundamental processes in sulfur dioxide (SO2) capture by calcium-based adsorbents for upper furnace, duct, and electrostatic precipitator (ESP) reaction sites. It examines the reactions in light of controlling mechanisms, effect of sorbent physical propert...

294

49 CFR 173.313 - UN Portable Tank Table for Liquefied Compressed Gases.  

Code of Federal Regulations, 2010 CFR

...for Liquefied Compressed Gases is referenced in...transport liquefied compressed gases. The table applies to each liquefied compressed gas that is identified...NA, 1954 Insecticide gases, flammable , n.o...2-tetrafluoroethane or Refrigerant gas R 114 7.0...

2010-10-01

295

Competitive adsorption study of CO 2 and SO 2 on Co II3[Co III(CN) 6] 2 using DRIFTS  

NASA Astrophysics Data System (ADS)

Diffuse reflectance infrared Fourier transform spectroscopy was used to study the competitive adsorption of CO 2 and SO 2 on the cobalt Prussian blue analogue Co II3[Co III(CN) 6] 2 at 298 K. Characteristic peaks for adsorbed CO 2 and SO 2 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 CO 2 and SO 2 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., Jr.; Thallapally, Praveen K.; McGrail, B. P.

2010-09-01

296

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

297

CO2, SO2, and H2S Degassing Related to the 2009 Redoubt Eruption, Alaska  

NASA Astrophysics Data System (ADS)

The 2009 eruption of Redoubt Volcano, Alaska was particularly well monitored for volcanic gas emissions with 35 airborne measurements of CO2, SO2, and H2S that span from October 2008 to August 2010. Increases in CO2 degassing were detected up to 5 months prior to the eruption and varied between 3630 and 9020 tonnes per day (t/d) in the 6 weeks prior to the eruption. Increased pre-eruptive CO2 degassing was accompanied by comparatively low S emission, resulting in molar C/S ratios that ranged between 30-60. However, the C/S ratio dropped to 2.4 coincident with the first phreatic explosion on March 15, 2009, and remained steady during the explosive (March 22 - April 4, 2009), effusive dome-building (April 5 - July 1, 2009), and waning phases (August 2009 onward) of the eruption. Observations of ice-melt rates, melt water discharge, and water chemistry in the months leading up to the eruption suggested that surface waters represented drainage from surficial, perched reservoirs of condensed magmatic steam and glacial meltwater. While the surface waters were capable of scrubbing many thousands of t/d of SO2, sampling of these fluids revealed that only a few hundred tonnes of SO2 was reacting to a dissolved component each day. This is also much less than the ~ 2100 t/d SO2 expected from degassing of magma in the upper crust (3-6.5 km), where petrologic analysis shows the final magma equilibration occurred. Thus, the high pre-eruptive C/S ratios observed could reflect bulk degassing of upper-crustal magma followed by nearly complete loss of SO2 in a magmatic-hydrothermal system. Alternatively, high C/S ratios could be attributed to degassing of low silica andesitic magma that intruded into the mid-crust in the 5 months prior to eruption; modeling suggests that mixing of this magma with pre-existing high silica andesite magma or mush would have caused a reduction of the C/S ratio to a value consistent with that measured during the eruption. Monitoring emissions regularly throughout the eruptive phases showed that the magmatic system degassed primarily as a closed system with approximately 59 and 66 % of the total CO2 and SO2, respectively, emitted during the explosive and dome growth periods. Maximum emission rates measured with airborne techniques were 33,110 t/d CO2, 16,650 t/d SO2, and 1230 t/d H2S. Pre-eruptive open system degassing accounted for only 14% of the total CO2 and 4% of total SO2, whereas post-eruptive passive degassing was responsible for 27 and 30 % of the total CO2 and SO2 with measurements extending over one year following the cessation of dome extrusion. SO2 made up on average 92% of the total sulfur degassing throughout the eruption. Primary volatile contents calculated from degassing and erupted magma volumes range from 0.9-2.1 wt. % CO2 and 0.27 - 0.56 wt. % S. Similar trends between volumes of estimated degassed magma and observed erupted magma during the eruptive period point to primary volatile contents of 1.25 wt. % CO2 and 0.35 wt. % S. Assuming these values, up to 30% additional unerupted magma degassed in the year following final dome emplacement.

Werner, C. A.; Kelly, P. J.; Evans, W.; Doukas, M. P.; McGimsey, R. G.; Neal, C. A.

2012-12-01

298

Extraction and quantification of SO2 content in wines using a hollow fiber contactor.  

PubMed

Sulfites [Formula: see text] or sulfur dioxide (SO2) is a preservative widely used in fruits and fruit-derived products. This study aims to propose a membrane contactor process for the selective removal and recovery of SO2 from wines in order to obtain its reliable quantification. Currently, the aspiration and Ripper methods offer a difficult quantification of the sulfite content in red wines because they involve evaporation steps of diluted compounds and a colorimetric assay, respectively. Therefore, an inexpensive and accurate methodology is not currently available for continuous monitoring of SO2 in the liquids food industry. Red wine initially acidified at pH?SO2, which is evaporated through the membrane pores filled with gas. Thus, SO2 is trapped in a colorless solution and the membrane contactor controls its transfer, decreasing experimental error induced in classical methods. Experimental results using model solutions with known concentration values of [Formula: see text] show an average extraction percentage of 98.91 after 4 min. On the other hand, two types of Chilean Cabernet Sauvignon wines were analyzed with the same system to quantify the content of free and total sulfites. Results show a good agreement between these methods and the proposed technique, which shows a lower experimental variability. PMID:23897976

Plaza, Andrea; Romero, Julio; Silva, Wladimir; Morales, Elizabeth; Torres, Alejandra; Aguirre, María J

2014-10-01

299

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

300

SO2 emissions from Popocatépetl volcano: emission rates and plume imaging using optical remote sensing techniques  

NASA Astrophysics Data System (ADS)

Sulfur dioxide emissions from Popocatépetl volcano in central Mexico were measured during the MILAGRO field campaign in March 2006. A stationary scanning DOAS (Differential Optical Absorption Spectrometer) was used to monitor the SO2 emissions from the volcano and the results were compared with traverses done with a COSPEC from the ground and a DOAS instrument on board an ultra-light aircraft. Daytime evolutions as well as day-to-day variation of the SO2 emissions are reported. A value of 2.45±1.39 Gg/day of SO2 is reported from all the daily averages obtained during the month of March 2006, with large variation in maximum and minimum daily averages of 5.97 and 0.56 Gg/day, respectively. The large short-term fluctuations in the SO2 emissions obtained could be confirmed through 2-D visualizations of the SO2 plume measured with a scanning imaging infrared spectrometer. This instrument, based on the passive detection of thermal radiation from the volcanic gas and analysis with FTIR spectrometry, is used for the first time for plume visualization of a specific volcanic gas. A 48-h forward trajectory analysis indicates that the volcanic plume was predominately directed towards the Puebla/Tlaxcala region (63%), followed by the Mexico City and Cuernavaca/Cuautla regions with 19 and 18% occurrences, respectively. 25% of the modeled trajectories going towards the Puebla region reached altitudes lower than 4000 m a.s.l. and all trajectories remained over this altitude for the other two regions.

Grutter, M.; Basaldud, R.; Rivera, C.; Harig, R.; Junkerman, W.; Caetano, E.; Delgado-Granados, H.

2008-04-01

301

SO2 emissions from Popocatépetl volcano: emission rates and plume imaging using optical remote sensing techniques  

NASA Astrophysics Data System (ADS)

Sulfur dioxide emissions from the Popocatépetl volcano in central Mexico were measured during the MILAGRO field campaign in March 2006. A stationary scanning DOAS (Differential Optical Absorption Spectrometer) was used to monitor the SO2 emissions from the volcano and the results were compared with traverses done with a COSPEC from the ground and a DOAS instrument on board an ultra-light aircraft. Daytime evolutions as well as day-to-day variation of the SO2 emissions are reported. A value of 2.45±1.39 Gg/day of SO2 is reported from all the daily averages obtained during the month of March 2006, with large variation in maximum and minimum daily averages of 5.97 and 0.56 Gg/day, respectively. The large short-term fluctuations in the SO2 emissions obtained could be confirmed through 2-D visualizations of the SO2 plume measured with a scanning imaging infrared spectrometer. This instrument, based on the passive detection of thermal radiation from the volcanic gas and analysis with FTIR spectrometry, is used for the first time for plume visualization of a specific volcanic gas. A 48-h forward trajectory analysis indicates that the volcanic plume was predominantly directed towards the Puebla/Tlaxcala region (63%), followed by the Mexico City and Cuernavaca/Cuautla regions with 19 and 18% occurrences, respectively. 25% of the modeled trajectories going towards the Puebla region reached altitudes lower than 4000 m a.s.l. but all trajectories remained over this altitude for the other two regions.

Grutter, M.; Basaldud, R.; Rivera, C.; Harig, R.; Junkerman, W.; Caetano, E.; Delgado-Granados, H.

2008-11-01

302

40 CFR 52.1923 - Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions...  

Code of Federal Regulations, 2014 CFR

...SO2 and Interstate pollutant transport provisions; What are the...PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL...SO2 and Interstate pollutant transport provisions; What are the...a.m. and 12 midnight. Air pollution control...

2014-07-01

303

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

304

A study of heterogeneous oxidation of SO2 in summer clouds  

NASA Astrophysics Data System (ADS)

Experimental determination of in-cloud oxidation of SO2 has been lacking because of an inability to distinguish SO4 in cloud water, derived from aerosol scavenging (i.e., produced from homogeneous gas phase oxidation), from that due to in-cloud SO2 oxidation, (SO4)in. A tracer technique has been developed in this laboratory that uses trace elements (M) to resolve the two SO4 components. Extensive data are reported in this paper on the use of Se as a tracer. Preliminary results are also included to test As and Sb as potential tracers. The technique is based on simultaneous determination of SO4 and M in cloud water (cw) and in out-of-cloud air (aa), and the knowledge of the relative scavenging efficiencies ? and ? of SO4 and M-bearing aerosols, respectively: (SO4)in = [(SO4/M)cw - ?/? (SO4/M)aa] (M)cw. Data from two events are presented which yield the scavenging ratio of SO4/Se as 1.04±0.29 and 1.04±0.19. The technique has been used to quantitatively determine in situ SO2 oxidation in six summer cloud systems during 1987-1989 at Whiteface Mountain, New York. Initially, cloud water samples were collected hourly, but in later sampling campaigns this interval was reduced to 15 min to better delineate the relationship between chemistry and meteorology in clouds. Aerosol collection was also reduced from 12 to 2 hours. Five cloud systems with pH ranging from 2.8 to 4.0 processed air which, based on our understanding of elemental signatures, had passed through the high-pollution emitting areas of the midwest. In individual samples, (SO4)in varied from 0 to 39%. The amount of (SO4)in did not vary dramatically from one sample to the next. The data appeared to be consistent with a flow-through reactor at the site through which updrafted air is passing. Where available, SO2 data in clear air and within the cloud yielded a mass balance consistent with our experimentally determined in situ SO4 formation. A sixth cloud event, a storm system which processed air largely from the north-northwest ("clean air"), yielded pH of 4.3 to 5.0 in the cloud water. Our tracer techniques based on both Se and As revealed no in situ oxidation of SO2. This was confirmed by our observation that SO2 concentration was low, and values in the cloud and in cloud-free air were equal. When data from all six summer cloud systems were pooled together, (SO4)in decreased with increasing pH with negligible oxidation above pH 4. Also, (SO4)in decreased smoothly with increasing aerosol SO4/Se ratio. Coal combustion is the primary source of S and Se in rural atmosphere in the northeast. Relative proportions of SO2 and SO4 are dependent on atmospheric oxidation. Enhancement in oxidation yields higher SO4/Se ratio and at the same time leaves less SO2 in the air for oxidation. A simple model is developed that enables an estimation of SO2 oxidation in clouds.

Husain, Liaquat; Dutkiewicz, V. A.; Hussain, M. M.; Khwaja, H. A.; Burkhard, E. G.; Mehmood, G.; Parekh, P. P.; Canelli, E.

1991-10-01

305

Dipolar Gases -- Theory  

NASA Astrophysics Data System (ADS)

In this chapter, we briefly review some important aspects of the theory of dipolar gases, focusing on those aspects in which the physics of dipolar gases differs qualitatively from that of non-dipolar ones.

Santos, Luis

2015-09-01

306

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

307

Electrical breakdown of gases  

Microsoft Academic Search

A collection of individual works on electrical discharges is presented. Topics covered include: fundamental processes in the electrical breakdown of gases; vacuum breakdown; spark breakdown in uniform fields; corona discharge; spark breakdown in non-uniform fields; breakdown voltage characteristics; irradiation and time lags; high-frequency breakdown of gases; laser-induced electrical breakdown of gases; spark channels; and electrode phenomena. (GHT)

J. M. Meek; J. D. Craggs

1978-01-01

308

RATE CONTROLLING PROCESSES AND ENHANCEMENT STRATEGIES IN HUMIDIFICATION FOR DUCT SO2 CAPTURE  

EPA Science Inventory

The report gives results of an investigation of the fundamental rate processes that govern sulfur capture in power plant ducts during humidification of flue gases. The specific application was the reactivation of partially sulfated calcium-based sorbents from in-furnace injection...

309

Kinetics of SO(2)-ethanol-water (SEW) fractionation of hardwood and softwood biomass.  

PubMed

SO(2)-ethanol-water (SEW) fractionation of forest residues (tree tops, stumps, branches) was investigated to demonstrate the potential of this method for forest biorefineries. The effect of fractionation time on dissolution of wood components was studied. Total mass balances of fractionation show that lignin and hemicelluloses are rapidly dissolved in the spent fractionation liquor whereas cellulose is fully preserved in the solid residue throughout the fractionation treatment. Within 20min treatment at 150°C (SO(2):EtOH:H2O=12:43.5:44.5, by weight, L:W ratio 6Lkg(-1)), 89% of hardwood lignin and 74% of hemicelluloses are dissolved. The corresponding values for softwood biomass are 64% and 74%, respectively, indicating slower delignification but equal hemicellulose removal. Additionally, sulfur content of the feedstocks, solid fractionation residues and spent liquors were analyzed to determine the degree of lignin sulfonation. The obtained results are compared with the stem wood fractionation results. PMID:24463411

Yamamoto, Minna; Iakovlev, Mikhail; van Heiningen, Adriaan

2014-03-01

310

CCN formation from DMS oxidation without SO2 acting as an intermediate  

NASA Astrophysics Data System (ADS)

An alternate pathway for generating cloud condensation nuclei (CCN) in the remote marine boundary layer (MBL) from the oxidation of biogenically-derived dimethyl sulfide (DMS) is proposed. This pathway invokes the production of H2SO4 from DMS without SO2 serving as an intermediate in the oxidation sequence. The H2SO4 thus produced then undergoes bimolecular nucleation to form tiny sulfate condensation nuclei (CN). These CN rapidly grow to sizes sufficiently large to act as CCN. While CCN production from SO2 appears to be inefficient, model calculations indicate that the alternate pathway is capable of generating significant numbers of new CCN in the MBL within a two to three day time period. The alternate pathway also suggests a strong coupling between oceanic emissions of DMS and the number of CCN in the MBL.

Lin, Xing; Chameides, W. L.

1993-04-01

311

A compilation of the absorption cross-sections of SO2 from 106 to 403 nm.  

NASA Astrophysics Data System (ADS)

Available spectrophotometric data on absorption cross-sections of SO2 for the gas phase from 106 to 403 nm at 293±10K have been evaluated and, where necessary, converted to a digital form. Plotting and comparing various overlapping data sets has demonstrated that systematic errors in wavelength and cross-section exist in the data sets. A scheme, which uses newer data sets that were recorded over limited wavelength ranges, to correct the wavelengths and cross-sections of older data sets, is discussed. In one region photoplate data were compared with spectrophotometric data. The spectral regions where reinvestigation is warranted are discussed. A data file of the cross-sections of SO2 was assembled from 106.1 to 403.7 nm at a resolution of 0.1 nm.

Manatt, S. L.; Lane, A. L.

1993-09-01

312

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

313

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

314

Separation of polar gases from nonpolar gases  

DOEpatents

The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

Kulprathipanja, Santi (Hoffman Estates, IL)

1986-01-01

315

Separation of polar gases from nonpolar gases  

DOEpatents

The separation of polar gases from nonpolar gases may be effected by passing a mixture of nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The porous support is pretreated prior to casting of the mixture thereon by contact with a polyhydric alcohol whereby the pores of the support are altered, thus adding to the increased permeability of the polar gas.

Kulprathipanja, S.

1986-08-19

316

Separation of polar gases from nonpolar gases  

DOEpatents

Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

Kulprathipanja, S.; Kulkarni, S.S.

1986-08-26

317

Separation of polar gases from nonpolar gases  

DOEpatents

Polar gases such as hydrogen sulfide, sulfur dioxide and ammonia may be separated from nonpolar gases such as methane, nitrogen, hydrogen or carbon dioxide by passing a mixture of polar and nonpolar gases over the face of a multicomponent membrane at separation conditions. The multicomponent membrane which is used to effect the separation will comprise a mixture of a glycol plasticizer having a molecular weight of from about 200 to about 600 and an organic polymer cast on a porous support. The use of such membranes as exemplified by polyethylene glycol and silicon rubber composited on polysulfone will permit greater selectivity accompanied by a high flux rate in the separation process.

Kulprathipanja, Santi (Hoffman Estates, IL); Kulkarni, Sudhir S. (Hoffman Estates, IL)

1986-01-01

318

Hot carrier induced photodesorption dynamics of SO2 from Ag(111)  

Microsoft Academic Search

The photon-driven (2.5 to 6.4 eV) desorption of SO2 (coverages up to 2.7 monolayers) on Ag(111) has been studied by time-of-flight mass spectrometry in combination with temperature programmed desorption and Auger electron spectroscopy. The photodesorption yields per incident photon increase with photon energy. Consistent with substrate-mediated excitation, the mean translational energy ?Etrans\\/2k? is constant (650 K) for photon energies between

Z.-J. Sun; S. Gravelle; R. S. Mackay; X.-Y. Zhu; J. M. White

1993-01-01

319

Mass Splitting of Staggered Fermion and $SO(2D)$ Clifford Algebra  

E-print Network

We present a new method to introduce rotationally invariant terms in staggered fermions which is based on an $SO(2D)$ Clifford algebra formulation, where $D$ means the number of space-time dimensions. We have four candidates for improved mass terms that can split the degenerate mass of staggered fermions. Among them, we analyze three types of combinations and find only one case that can identify with the light single Dirac mode.

M. Hatakeyama; H. Sawanaka; H. So

2006-09-28

320

Computed linewidths of SO2. [for type A and type B bands  

NASA Technical Reports Server (NTRS)

Self-broadened and foreign-gas (N2 and O2) broadened linewidths of sulfur dioxide, for both type A and type B bands, have been calculated using the Anderson-Tsao-Curnutte theory of line broadening. Computed values of these linewidths at 300 K are given for all the transitions with J or = 20 and K sub minus 1 or = 15. Air-broadened linewidths have also been calculated for SO2 at 250 K and 200 K for these transitions.

Tejwani, G. D. T.

1972-01-01

321

SO2-Ethanol-Water (SEW) Pulping: II. Kinetics for Spruce, Beech, and Wheat Straw  

Microsoft Academic Search

SO2-ethanol-water (SEW) delignification kinetics for spruce, beech, and wheat straw are presented. All these species produce pulps using SEW cooking liquor and follow first order delignification kinetics at similar bulk delignification rates. However, residual delignification is much slower for beech than for spruce.The hemicelluloses retention (135°C) and cellulose degradation kinetics are also characterized for beech SEW pulping. Xylan and glucomannan

Mikhail Iakovlev; Herbert Sixta; Adriaan van Heiningen

2011-01-01

322

The formation of submicron aerosol particles, HCl and SO 2 in straw-fired boilers  

Microsoft Academic Search

The concentration of submicron particles, HCl and SO2 in the flue gas from the combustion of straw from wheat, barley and oil seed rape was studied by field measurements on two utility boilers. The concentration of submicron particles varies from 75–2000mgNm-3§§1Nm3 (normal cubic meter)=1m3 gas measured at 1atm and 0°C. and the mean diameter in the range from 0.2 to

Kurt A. Christensen; Michael Stenholm; Hans Livbjerg

1998-01-01

323

Scrubbing of particulate-laden-SO 2 in a hybrid column  

Microsoft Academic Search

In this article, the performance of a two-stage hybrid (spray-cum-bubble) column on the scrubbing of particulate-laden-SO2 using water and dilute NaOH is reported. The present system deals with a tapered section in order to achieve the bubble regime.\\u000a On the other hand, a two-phase critical flow atomizer is used for generating finer drops with high degree of spray uniformity.\\u000a Detailed

Amitava Bandyopadhyay; Manindra Nath Biswas

2008-01-01

324

SO2-Ethanol-Water (SEW) Pulping: I. Lignin Determination in Pulps and Liquors  

Microsoft Academic Search

Quantitative determination of lignin in SO2-ethanol-water (SEW) pulps and spent liquors is described. The methods developed for conventional sulfite pulping are successfully applied to the SEW process. Linear correlations between Klason\\/total lignin content and kappa number are found over a wide pulp yield range for spruce, beech, and wheat straw. Lignin content of the spruce spent SEW liquors is determined

Mikhail Iakovlev; Adriaan van Heiningen

2011-01-01

325

Predicting CO2 and SO2 emissions in the Baltic States through reorganization of energy infrastructure.  

PubMed

The paper deals with predicting carbon dioxide and sulphur dioxide emissions generated by power production sector in the Baltic States in period up to year 2020. The economies of Lithuania, Latvia and Estonia are rapidly growing therefore forecast of emissions related with this occurrence becomes very important. The Ignalina Nuclear Power Plant (INPP), one of the largest in the world, is situated in the region. Two power production scenarios are modelled to investigate changes in power sector's emissions expected as the consequences of the coming closure of Ignalina NPP. Power market was assumed to be common for all three Baltic countries and was modelled by applying the Balmorel model. The planned closure of Ignalina NPP will bring restructuring of Lithuania power production sector and will change also power transmission between countries. Predictive identified the potential of investments for new modern power generation technologies. At the same time, modelling results show in both scenarios that CO(2) and SO(2) emissions from power production in the Baltic region will increase. The increment of emissions is discussed in the context of meeting requirements of UNFCCC Kyoto protocol and EC Directives. Despite of CO(2) emissions increase the Kyoto protocol's requirements may be expected. At the same time, SO(2) formation in Lithuania power sector may exceed the limits of the EU Council Directive 2001/80/EB therefore the additional measures to control SO(2) emissions have to be investigated. PMID:15337350

Denafas, Gintaras; Sitnikovas, Denisas; Galinis, Arvydas; Kudrenickis, Ivars; Klavs, Gaidis; Kuusik, Rein

2004-10-01

326

New instrument for measuring atmospheric concentrations of non-OH oxidants of SO2  

NASA Astrophysics Data System (ADS)

Oxidation of sulphur dioxide (SO2) by the hydroxyl radical (OH) is considered the main source of gaseous sulphuric acid (H2SO4) in the atmosphere. However, recent studies suggest that also non-OH oxidants can have a substantial role in H2SO4 production. Some of these non-OH oxidants of SO2 are stabilized Criegee intermediates (SCIs) which are formed in the ozonolysis of alkenes. An FR-CI-APi-TOF instrument for measuring the total concentration of all non-OH oxidants (X) reacting with SO2 at a reasonable rate is presented here. The instrument consists of a flow reactor (FR) and a chemical ionisation (CI) atmospheric pressure interface (APi) time of flight (TOF) mass spectrometer. The first field measurements at a boreal forest site indicated that the summertime concentration, production rate and apparent lifetime of X were (0.3-2.0) × 106 cm-3, (0.3-1.9) × 106 cm-3 s-1 and 0.3-5.0 s, respectively. The estimated concentration and production rate of SCIs formed in the ozonolysis of monoterpenes were substantially lower, possibly indicating the presence of SCIs from other alkenes. Detailed instrument characteristics will be presented and further instrument development will be discussed.

Taipale, Risto; Sarnela, Nina; Rissanen, Matti; Junninen, Heikki; Rantala, Pekka; Korhonen, Frans; Siivola, Erkki; Berndt, Torsten; Kulmala, Markku; Mauldin, Roy L., III; Petäjä, Tuukka; Sipilä, Mikko

2014-05-01

327

SO2 plume height retrieval from UV satellite measurements in support to aviation control  

NASA Astrophysics Data System (ADS)

The Support to Aviation Control Service (SACS), operated at our institute, uses multi-sensor UV-visible and infrared satellite measurements to provide near real-time information on volcanic ash and SO2 concentrations. In case of enhanced SO2 concentrations, notifications are send out to subscribing organisations and individuals, with details regarding the volcanic event. This information may be used by aviation control organisations to judge the risc to air traffic and provide possible alternative routing. One of the latest additions to the system is information on the altitude of SO2 plumes, based on UV measurements of the GOME-2 sensors on the platforms METOP-A and METOP-B. Further improvement of this system is ongoing. This poster shows examples of plume height retrieval from GOME-2 (METOP-A and -B) and OMI (EOS-AURA). Results are shown for a number of recent major volcanic eruptions, each with different characteristics. The applied technique to retrieve altitude information will be discussed, as well as the applicability, quality and limitations of the method.

van Gent, Jeroen; Brenot, Hugues; Lerot, Christophe; Theys, Nicolas; Van Roozendael, Michel

2014-05-01

328

Middle UV to Near-IR Spectrum of Electron-Excited SO2  

NASA Technical Reports Server (NTRS)

We investigated the electron impact-induced fluorescence spectrum of SO2 to provide excitation cross sections for modeling Io's mission spectrum and analyzing Cassini Imaging Science Subsystem observations. The electron-excited middle-ultraviolet visible optical near-infrared (VOIR) emission spectrum of SO2 gas was generated in the laboratory and studied from 2000 to 11,000 A at a resolution of (Delta)(lamda) approximately 2.5 A full width at half maximum (FWHM). The VOIR laboratory spectrum longward of 6000 A consists entirely of S I, II and O I, II multiplets for electron impact energies above approximately 15 eV. Between 2000 and 6000 A, we find previously identified molecular bands from both SO and SO2. This work represents a significant improvement in spectral resolution over our earlier work done at 18 A FWHM. From a measurement of the medium-resolution spectrum, we provide detailed 25- and 100-eV emission cross sections for spectral features from 2000 to 11,000 A . On the basis of these data, we suggest future ground-based and satellite telescopic observations in the VOIR that are of promise for understanding Io's atmosphere.

Ajello, Joseph M.; Aguilar, Alejandro; Mangina, Rao S.; James, Geoffrey K.; Geissler, Paul; Trafton, Laurence

2008-01-01

329

Numerical Study of the Simultaneous Oxidation of NO and SO2 by Ozone.  

PubMed

This study used two kinetic mechanisms to evaluate the oxidation processes of NO and SO2 by ozone. The performance of the two models was assessed by comparisons with experimental results from previous studies. The first kinetic mechanism was a combined model developed by the author that consisted of 50 species and 172 reactions. The second mechanism consisted of 23 species and 63 reactions. Simulation results of both of the two models show under predictions compared with experimental data. The results showed that the optimized reaction temperature for NO with O3 ranged from 100~200 °C. At higher temperatures, O3 decomposed to O2 and O, which resulted in a decrease of the NO conversion rate. When the mole ratio of O3/NO was greater than 1, products with a higher oxidation state (such as NO3, N2O5) were formed. The reactions between O3 and SO2 were weak; as such, it was difficult for O3 to oxidize SO2. PMID:25642689

Li, Bo; Zhao, Jinyang; Lu, Junfu

2015-01-01

330

A kinetic study of the CH2OO Criegee intermediate self-reaction, reaction with SO2 and unimolecular reaction using cavity ring-down spectroscopy.  

PubMed

Criegee intermediates are important species formed during the ozonolysis of alkenes. Reaction of stabilized Criegee intermediates with various species like SO2 and NO2 may contribute significantly to tropospheric chemistry. In the laboratory, self-reaction can be an important loss pathway for Criegee intermediates and thus needs to be characterized to obtain accurate bimolecular reaction rate coefficients. Cavity ring-down spectroscopy was used to perform kinetic measurements for various reactions of CH2OO at 293 K and under low pressure (7 to 30 Torr) conditions. For the reaction CH2OO + CH2OO (8), a rate coefficient k8 = (7.35 ± 0.63) × 10(-11) cm(3) molecule(-1) s(-1) was derived from the measured CH2OO decay rates, using an absorption cross section value reported previously. A rate coefficient of k4 = (3.80 ± 0.04) × 10(-11) cm(3) molecule(-1) s(-1) was obtained for the CH2OO + SO2 (4) reaction. An upper limit for the unimolecular CH2OO loss rate coefficient of 11.6 ± 8.0 s(-1) was deduced from studies of reaction (4). SO2 catalysed CH2OO isomerization or intersystem crossing is proposed to occur with a rate coefficient of (3.53 ± 0.32) × 10(-11) cm(3) molecule(-1) s(-1). PMID:25553776

Chhantyal-Pun, Rabi; Davey, Anthony; Shallcross, Dudley E; Percival, Carl J; Orr-Ewing, Andrew J

2015-02-01

331

Effect of SO2 on the transport properties of an imidazolium ionic liquid and its lithium solution.  

PubMed

Transport coefficients have been measured as a function of the concentration of sulfur dioxide, SO(2), dissolved in 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [BMMI][Tf(2)N], as well as in its lithium salt solution, Li[Tf(2)N]. The SO(2) reduces viscosity and density and increases conductivity and diffusion coefficients in both the neat [BMMI][Tf(2)N] and the [BMMI][Tf(2)N]-Li[Tf(2)N] solution. The conductivity enhancement is not assigned to a simple viscosity effect; the weakening of ionic interactions upon SO(2) addition also plays a role. Microscopic details of the SO(2) effect were unraveled using Raman spectroscopy and molecular dynamics (MD) simulations. The Raman spectra suggest that the Li(+)-[Tf(2)N] interaction is barely affected by SO(2), and the SO(2)-[Tf(2)N] interaction is weaker than previously observed in an investigation of an ionic liquid containing the bromide anion. Transport coefficients calculated by MD simulations show the same trend as the experimental data with respect to SO(2) content. The MD simulations provide structural information on SO(2) molecules around [Tf(2)N], in particular the interaction of the sulfur atom of SO(2) with oxygen and fluorine atoms of the anion. The SO(2)-[BMMI] interaction is also important because the [BMMI] cations with above-average mobility have a larger number of nearest-neighbor SO(2) molecules. PMID:21726096

Monteiro, Marcelo J; Ando, Rômulo A; Siqueira, Leonardo J A; Camilo, Fernanda F; Santos, Paulo S; Ribeiro, Mauro C C; Torresi, Roberto M

2011-08-11

332

Quantifying HCl and SO2 adsorption by tephra in volcanic eruptions  

NASA Astrophysics Data System (ADS)

Tephra-gas interaction in eruption plumes leads to scavenging of volatiles (SO2, HCl, HF) and forms soluble salts and aqueous acids on tephra surfaces. The presence of these compounds may induce a number of environmental effects upon tephra emission and deposition. These may range from acid damage to vegetation surfaces, to the release of key nutrients or toxic metals into lake or surface ocean waters. It has also been suggested that alterations to tephra surface chemistry imparted by volatile scavenging may contribute to in-plume particle aggregation, so influencing tephra dispersal and fallout. Gaining further insight into the possible effects associated with, or indirectly resulting from, gas-tephra interaction necessitates a renewed mechanistic investigation of the latter. Such an undertaking must expand upon the three stage, 'solid aerosol adhesion / volatile adsorption / acid condensation' scavenging model proposed by Oskarsson in 1980. We present the results of SO2 and HCl uptake experiments on tephrite, phonolite, dacite and rhyolite glass powders conducted over a range of in-plume temperatures (100-800° C). Using a suite of analytical techniques, we identified coupled adsorption-diffusion mechanisms driving the scavenging of SO2 and HCl. These volatiles reacted with Ca- and Na-bearing surface sites to form CaSO4, Na2SO4 and NaCl deposits; uptake is thought to be sustained respectively by near-surface co-diffusion of O2- with Ca2+ or Na+, and interdiffusion between H+ and Na+. The scavenging of SO2 and HCl was also subject to complex thermal, temporal and compositional controls which were strongly influenced by the chemical composition of the glass. By reference to our experimental findings and to current plume evolution and conduit flow models, we are able to estimate the potential for SO2 and HCl uptake by direct adsorption onto tephra particles within the eruption plume. Our findings therefore highlight those eruptive environments where in-plume gas adsorption may significantly alter tephra surface chemistry, and in doing so, may dictate the intensity of any induced chemical effects in the plume or in receiving environments.

Ayris, Paul Martin; Delmelle, Pierre; Maters, Elena; Dingwell, Donald Bruce

2013-04-01

333

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

334

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

335

Satellite Observations of NO2 Trend over Romania  

PubMed Central

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

Voiculescu, Mirela; Georgescu, Lucian

2013-01-01

336

Stratospheric NO and NO2 abundances from ATMOS Solar-Occultation Measurements  

Microsoft Academic Search

Using results from a time-dependent photochemical model to calculate the diurnal variation of NO and NO2, we have corrected Atmospheric Trace MOlecule Spectroscopy (ATMOS) solar-occultation retrievals of the NO and NO2 abundances at 90° solar zenith angle. Neglecting to adjust for the rapid variation of these gases across the terminator results in potential errors in retrieved profiles of ?20% for

M. J. Newchurch; M. Allen; M. R. Gunson; R. J. Salawitch; G. B. Collins; K. H. Huston; M. M. Abbas; M. C. Abrams; A. Y. Chang; D. W. Fahey; R. S. Gao; F. W. Irion; M. Loewenstein; G. L. Manney; H. A. Michelsen; J. R. Podolske; C. P. Rinsland; R. Zander

1996-01-01

337

ZnO Nanobelt Based Conductometric H2 and NO2 Gas Sensors  

Microsoft Academic Search

Conductometric H2 and NO2 gas sensors based on single-crystalline ZnO nanobelt sensitive layers have been developed. These layers were deposited using a rf magnetron sputterer. TEM and SEM characterization methods were employed to study the morphology of the nanobelts. These sensors were exposed to H2 and NO2 gases at operating temperatures between 225degC and 420degC. Study showed that sensors responded

A. Z. Sadek; W. Wlodarski; K. Kalantar-zadeh; S. Choopun

2005-01-01

338

Lyman Alpha Camera for Io's SO2 atmosphere and Europa's water plumes  

NASA Astrophysics Data System (ADS)

The Student Lyman-Alpha Mapper (SLAM) was conceived for the Io Volcano Observer (IVO) mission proposal (McEwen et al., 2014) to determine the spatial and temporal variations in Io's SO2 atmosphere by recording the H Ly-? reflection over the disk (Feldman et al., 2000; Feaga et al., 2009). SO2 absorbs at H Ly-?, thereby modulating the brightness of sunlight reflected by the surface, and measures the density of the SO2 atmosphere and its variability with volcanic activity and time of day. Recently, enhancements at the Ly-? wavelength (121.57 nm) were seen near the limb of Europa and interpreted as active water plumes ~200 km high (Roth et al., 2014). We have a preliminary design for a very simple camera to image in a single bandpass at Ly-?, analogous to a simplified version of IMAGE EUV (Sandel et al. 2000). Our goal is at least 50 resolution elements across Io and/or Europa (~75 km/pixel), ~3x better than HST STIS, to be acquired at a range where the radiation noise is below 1E-4 hits/pixel/s. This goal is achieved with a Cassegrain-like telescope with a 10-cm aperture. The wavelength selection is achieved using a simple self-filtering mirror in combination with a solar-blind photocathode. A photon-counting detector based on a sealed image intensifier preserves the poisson statistics of the incoming photon flux. The intensifier window is coated with a solar-blind photocathode material (CsI). The location of each photon event is recorded by a position-sensitive anode based on crossed delay-line or wedge-and-strip technology. The sensitivity is 0.01 counts/pixel/sec/R, sufficient to estimate SO2 column abundances ranging from 1E15 to 1E17 per cm2 in a 5 min (300 sec) exposure. Sensitivity requirements to search for and image Europa plumes may be similar. Io's Ly-? brightness of ~3 kR exceeds the 0.8 kR brightness of Europa's plume reported by Roth et al. (2014), but the plume brightness is a direct measurement rather than inferring column abundance from absorption. Also, the radiation-induced noise is lower at Europa, permitting longer exposure times and imaging at closer range. This is a very simple instrument with no moving parts, a mass of 4 kg (plus 1.7 kg radiation shielding), and it needs 4 W power. It has no special accommodation requirements and would simply collect data in ride-along mode during point-and-stare sequences. Feaga, L.M., et al. (2009) Io's dayside SO2 atmosphere, Icarus 201, 570-584 (2009). Feldman, P.D., et al., (2000) Lyman-? imaging of the SO2 distribution on Io, Geophys. Res. Lett., 27, 1787-1790. McEwen, A.S. et al. (2014) Io Volcano Observer (IVO): Budget travel to the outer Solar System. Acta Astronautica 93, 539-544. Roth, L. et al. (2014) Transient water vapor at Europa's south pole. Science 343, 171. Sandel, B., et al. (2000) The Extreme Ultraviolet Imager investigation for the IMAGE mission. Space Sci. Rev. 91, 197-242.

McEwen, Alfred S.; Sandel, Bill; Schneider, Nick

2014-05-01

339

Formaldehyde and its relation to CO, PAN, and SO2 in the Houston-Galveston airshed  

NASA Astrophysics Data System (ADS)

The Houston-Galveston Airshed (HGA) is one of the major metropolitan areas in the US that is classified as a nonattainment area of federal ozone standards. Formaldehyde (HCHO) is a key species in understanding ozone related air pollution; some of the highest HCHO concentrations in North America have been reported for the HGA. We report on HCHO measurements in the HGA from summer 2006. Among several sites, maximum HCHO mixing ratios were observed in the Houston Ship Channel (HSC), a region with a very high density of industrial/petrochemical operations. HCHO levels at the Moody Tower (MT) site close to downtown were dependent on the wind direction: southerly maritime winds brought in background levels (0.5-1 ppbv) while trajectories originating in the HSC resulted in high HCHO (up to 31.5 ppbv). Based on the best multiparametric linear regression model fit, the HCHO levels at the MT site can be accounted for as follows: 38.5±12.3% from primary vehicular emissions (using CO as an index of vehicular emission), 24.1±17.7% formed photochemically (using peroxyacetic nitric anhydride (PAN) as an index of photochemical activity) and 8.9±11.2% from industrial emissions (using SO2 as an index of industrial emissions). The balance 28.5±12.7% constituted the residual which cannot be easily ascribed to the above categories and/or which is transported into the HGA. The CO related HCHO fraction is dominant during the morning rush hour (06:00-09:00 h, all times are given in CDT); on a carbon basis, HCHO emissions are up to 0.7% of the CO emissions. The SO2 related HCHO fraction is significant between 09:00-12:00 h. After 12:00 h HCHO is largely formed through secondary processes. The HCHO/PAN ratios are dependent on the SO2 levels. The SO2 related HCHO fraction at the downtown site originates in the ship channel. Aside from traffic-related primary HCHO emissions, HCHO of industrial origin serves as an appreciable source for OH in the morning.

Rappenglück, B.; Dasgupta, P. K.; Leuchner, M.; Li, Q.; Luke, W.

2010-03-01

340

Formaldehyde and its relation to CO, PAN, and SO2 in the Houston-Galveston airshed  

NASA Astrophysics Data System (ADS)

The Houston-Galveston Airshed (HGA) is one of the major metropolitan areas in the US that is classified as a nonattainment area of Federal ozone standards. Formaldehyde (HCHO) is a key species in understanding ozone related air pollution; some of the highest HCHO concentrations in North America have been reported for the HGA. We report on HCHO measurements in the HGA from summer 2006. Among several sites, maximum HCHO mixing ratios were observed in the Houston Ship Channel (HSC), a region with a very high density of industrial/petrochemical operations. HCHO levels at the Moody Tower (MT) site close to downtown were dependent on the wind direction: southerly maritime winds brought in background levels (0.5-1 ppbv) while trajectories originating in the HSC resulted in high HCH (up to 31.5 ppbv). Based on the best multiparametric linear regression model fit, the HCHO levels at the MT site can be accounted for as follows: 38.5±12.3% from primary vehicular emissions (using CO as an index of vehicular emission), 24.1±17.7% formed photochemically (using peroxyacetic nitric anhydride (PAN) as an index of photochemical activity) and 8.9±11.2% from industrial emissions (using SO2 as an index of industrial emissions). The balance 28.5±12.7% constituted the residual which cannot be easily ascribed to the above categories and/or which is transported into the HGA. The CO related HCHO fraction is dominant during the morning rush hour (06:00-09:00 h, all times are given in CDT); on a carbon basis, HCHO emissions are up to 0.7% of the CO emissions. The SO2 related HCHO fraction is significant between 09:00-12:00 h. After 12:00 h HCHO is largely formed through secondary processes. The HCHO/PAN ratios are dependent on the SO2 levels. The SO2 related HCHO fraction at the downtown site originates in the ship channel. Aside from traffic-related primary HCHO emissions, HCHO of industrial origin serves as an appreciable source for OH in the morning.

Rappenglück, B.; Dasgupta, P. K.; Leuchner, M.; Li, Q.; Luke, W.

2009-11-01

341

Synthesis of N-Doped meso-macroporous carbon and its application to SO2 absorption  

NASA Astrophysics Data System (ADS)

N-Doped meso-macroporous carbon materials were synthesized using melamine-formaldehyde resin as carbon precursor and silica spheres as a removable template. The as-synthesized carbon materials with a bimodal pores structure (about 3.9 and ˜50-200 nm) display a high surface nitrogen content of 30 wt %. The macropores of carbon materials can be modulated by changing the diameter of template. The SO2 adsorption experiments demonstrate a high adsorption capacity of 78.6 mg g-1 and a considerable stability even over 9 cycles for the carbon materials.

Liu, Chao; Zhang, Lei; Hu, Yongqi; Chen, Aibing; Wang, Xiaojing

2014-12-01

342

Observations of the chemical properties of dew on vegetation that affect the dry deposition of SO2  

NASA Astrophysics Data System (ADS)

Experiments were conducted to examine the chemical properties of dew (and guttation) that affect the dry deposition of SO2 to prairie grasses of tall stature and mixed broadleaf plants of short stature. For 2-3 hours after sunrise, liquid samples were extracted directly from the upper ? of the plant canopies and from surrogate surfaces, concurrently with selected atmospheric observations. Chemical analyses showed that aqueous concentrations of S(IV), SO42-, and several other ions in the leaf wetness were often high compared to values typically found in rain, while NH4+ was not very abundant. Guttation produced substantial amounts of liquid, which mainly contributed Cl- to the leaf wetness. The dry deposition of S(IV) to leaf wetness was not always apparently limited by aqueous oxidation by O3, especially when aerodynamic resistances limited the maximum potential deposition velocity to less than 0.5 cm/s at a height of 8 m. A more effective oxidant than atmospheric O3 or NO2 could have been present and could have lessened the inferred substantial contributions of particle deposition to leaf wetness SO42-. Foliar uptake of NO3- and SO42- was significant after sunrise. The pH of the leaf wetness in the broadleaf vegetation seemed to have a lower limit of about 5.3, possibly because of neutralization by substances leached from leaves, while the pH of the grasses reached values as low as 4.5 when the amount of leaf wetness was small. The potassium ion concentration in leaf wetness appeared to be an effective marker for leaf leaching.

Wesely, M. L.; Sisterson, D. L.; Jastrow, J. D.

1990-05-01

343

Auger electron spectroscopy investigation of SO 2/Zr(0 0 0 1)  

NASA Astrophysics Data System (ADS)

The adsorption of SO 2 on Zr(0 0 0 1) at 150 K has been investigated under ultrahigh vacuum (UHV) conditions. Auger electron spectroscopy (AES) reveals saturation of both sulfur and oxygen signals at exposures of about 1 Langmuir (L). Changes in the overlapping Zr(MNV) + S(LMM) feature as well as in the Zr(MNN) feature are discussed. In particular, the Zr(MNN) feature changes with both exposure and annealing history, complicating the identification of sulfur using Auger peak-to-peak height ratios. We propose that SO 2 dissociates on Zr(0 0 0 1) under these conditions, since no thermal desorption of sulfur dioxide is detected for exposures up to 5 L. However, the desorption of small quantities of 34 and 32 amu species near 250 K is observed by temperature programmed desorption (TPD) measurements. Integrated desorption peak areas of these species saturate near 1 L, consistent with the saturation behavior observed by AES. Electron bombardment (500 eV) reduces H 2S desorption presumably by removing surface hydrogen via electron stimulated mechanisms, but has no effect on Auger spectra.

Stojilovic, N.; Tokash, J. C.; Ramsier, R. D.

2004-03-01

344

Infrared spectroscopy of hydrogen-bonded CHCl3-SO2 in the gas phase  

NASA Astrophysics Data System (ADS)

A molecular association between chloroform and sulfur dioxide in the gas phase at room temperature was studied by Fourier transform infrared spectroscopy. Since the intensity of the CH-stretching fundamental vibration of monomer chloroform is very weak but much stronger upon complexation, a simple subtraction procedure isolated the CH-stretching vibration spectrum of the complex. The presence of a 1:1 complex was confirmed by two dilution series, where the monomer concentrations were varied. The molecular association manifested itself as a shift of the peak absorbance of the CH-stretching vibration of CHCl3-SO2 by +7cm-1 and of the CD-stretching vibration of CDCl3-SO2 by +5cm-1 to higher wave numbers compared to monomer chloroform, accompanied by a considerable broadening of the band contour. In agreement with previous ab initio calculations, this indicates a "blueshifting" or more appropriately, a "C-H contracting" hydrogen bond between chloroform and sulfur dioxide. An estimate of the complex concentration was made based on ab initio calculations for the integrated band strength and the measured spectrum. With this estimate, the equilibrium constant Kp (295K )=0.014 (po=105Pa) for the dimerization was calculated, providing one of the very few cases where the formation of a hydrogen-bonded gas phase complex at room temperature could be quantitatively studied by infrared spectroscopy.

Chung, Susan; Hippler, Michael

2006-06-01

345

Projections of SO2, NOx and carbonaceous aerosols emissions in Asia  

NASA Astrophysics Data System (ADS)

Estimates of Asian emissions of air pollutants and carbonaceous aerosols and their mid-term projections have been changing significantly in the last years. The remote sensing community has shown that increase in NOx in Central East Asia is much stronger than any of the emission inventories or projections indicated so far. A number of studies reviewing older estimates appeared. Here, we review the key contributions and compare them to the most recent results of the GAINS model application for Asia and to the SRES projections used in the IPPC work. The recent projections indicate that the growth of emissions of SO2 in Asia should slow down significantly towards 2010 or even stabilize at the current level. For NOx, however, further growth is projected although it will be most likely slower that in the last decade, owing to introduction of measures in transport. Emissions of carbonaceous aerosols (black carbon and organic carbon) are expected to decline after 2010, largely due to reduced use of biofuels in residential sector and efficiency improvements. The estimates of these emissions are burdened with significantly larger uncertainties than SO2 and NOx; even for the year 2000 the differences in estimates between studies are up to a factor of 2.

Klimont, Z.; Cofala, J.; Xing, J.; Wei, W.; Zhang, C.; Wang, S.; Kejun, J.; Bhandari, P.; Mathur, R.; Purohit, P.; Rafaj, P.; Chambers, A.; Amann, M.; Hao, J.

2009-09-01

346

SO2 degassing from Turrialba Volcano linked to seismic signatures during the period 2008-2012  

NASA Astrophysics Data System (ADS)

In 1996, after 150 years of relative calm, Turrialba volcano was reawakening. A visible plume and serious damage to surrounding vegetation due to acid rain are the most obvious signals. As part of the NOVAC (Network for Observation of Volcanic and Atmospheric Change) project, four gas-monitoring stations were initially installed on the west flank of the volcano with the purpose of measuring sulphur dioxide emissions during this period of increased activity using the Scanning-DOAS technique. We present here the results of semi-continuous gas flux measurements over a period of five years (from 2008 to 2012), providing a novel data set that documents a relatively rapid increase in SO2 fluxes from around 350 t day-1 to around 4000 t day-1 leading up to an eruptive period, followed by a gradual return to the former baseline values. Gas flux data were also compared with seismic data for selected periods of interest, providing insights into the link between degassing and seismicity that allowed us to identify displacements of the seismic source location. Monitoring of SO2 thus complements seismic monitoring as a forecasting tool for eruptive events. Such monitoring is critical considering the proximity of Turrialba to the Central Valley, an area inhabited by more than 50% of Costa Rica's population.

Conde, V.; Bredemeyer, S.; Duarte, E.; Pacheco, J. F.; Miranda, S.; Galle, B.; Hansteen, T. H.

2013-12-01

347

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

348

Trends in source gases  

NASA Technical Reports Server (NTRS)

Source gases are defined as those gases that, by their breakdown, introduce into the stratosphere halogen, hydrogen, and nitrogen compounds that are important in stratospheric ozone destruction. Given here is an update of the existing concentration time series for chlorocarbons, nitrous oxide, and methane. Also reviewed is information on halogen containing species and the use of these data for establishing trends. Also reviewed is evidence on trends in trace gases that influence tropospheric chemistry and thus the tropospheric lifetimes of source gases, such as carbon dioxide, carbon monoxide, or nitrogen oxides. Much of the information is given in tabular form.

Ehhalt, D. H.; Fraser, P. J.; Albritton, D.; Cicerone, R. J.; Khalil, M. A. K.; Legrand, M.; Makide, Y.; Rowland, F. S.; Steele, L. P.; Zander, R.

1989-01-01

349

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

EPA Science Inventory

Tropospheric ozone is the third strongest greenhouse gas, and has the highest uncertainty in radiative forcing of the top five greenhouse gases. Throughout the troposphere, ozone is produced by radical oxidation of nitrogen oxides (NO,x =NO+NO2). In the uppe...

350

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

351

Fractionation of sulfur isotopes during heterogeneous oxidation of SO2 in the atmosphere  

NASA Astrophysics Data System (ADS)

Sulfate and sulfur dioxide play an important role in environmental chemistry and climate, particularly through their effect on aerosols. Processing of aerosol through sulfate addition in clouds, which causes both hygroscopicity changes and mass increases, has been shown to modify the cloud condensation nucleus spectrum, leading to important climatological effects (Bower et al. 1997, Hegg et al. 2004). However, the uptake of sulfate and SO2 to aerosol in clouds is not well constrained, nor is it resolved for different particle types and sizes (Kasper-Giebl et al. 2000, Barrie et al. 2001). Measurements of stable sulfur isotopes can be used to investigate the chemistry of SO2 in the environment, providing insight into sources, sinks and oxidation pathways. Typical isotopic compositions for many sources have been measured, and the major current limitation is the lack of reliable fractionation factors - characteristic changes in isotopic composition caused by chemical reactions - with which to interpret the data. Laboratory values of fractionation factors for the major oxidation reactions have been measured in previous work, however there are no measurements or models to represent isotopic fractionation during heterogeneous oxidation on complex atmospheric surfaces. In this work the sulfur isotopic fractionation factors for SO2 oxidation have been measured on Sahara dust, obtained from the Cape Verde Islands, and sea salt aerosol, which was synthesised in the laboratory according to Millero (1974), modified to contain no sulfate. Sulfur dioxide with a known isotopic composition was oxidised on these surfaces under a variety of conditions including irradiation and ozonation, and the sulfur isotopic composition of the product sulfate was measured with the Cameca NanoSIMS 50. These laboratory results were then used to investigate the uptake of sulfur to particles in an orographic cloud during the HCCT campaign. The campaign took place at the Schmücke mountain in Germany and used connected flow conditions between upwind, in-cloud and downwind measurement sites to study the evolution of air masses due to cloud processing. NanoSIMS isotopic analysis was used to constrain the formation and uptake of sulfate in the cloud. Oxidation by a radical chain reaction catalysed by transition metals was seen to be the most important oxidation reaction occurring in two out of three measured cloud events.

Harris, E. J.; Sinha, B.; Hoppe, P.; Crowley, J.; Borrmann, S.; Foley, S. F.; Gnauk, T.; Van Pinxteren, D.; Herrmann, H.

2011-12-01

352

Effect of artificial acid rain and SO2 on characteristics of delayed light emission.  

PubMed

The structure and function of chloroplast in plant leaves can be affected by acid rain and air pollution. The photosystem II in a plant is considered the primary site where light-induced delayed light emission (DLE) is produced. With the lamina of zijinghua (Bauhinia variegata L.) and soybean (Glycine max (L.) Merr.) as testing models, we studied the effects of artificial acid rain and SO2 on characteristics of DLE by using a home-made weak luminescence detection system. The results show that the changes in DLE intensity of green plants can reflect the changes in chloroplast intactness and function. With proper calibration, DLE may provide an alternative means of evaluating environmental acid stress on plants. The changes in DLE intensity may provide a new approach for the detection of environmental pollution and its impact on the ecosystem. PMID:15685660

Wang, Chenglong; Xing, Da; Zeng, Lizhang; Ding, Chunfeng; Chen, Qun

2005-01-01

353

Transport of Trace Gases  

NASA Technical Reports Server (NTRS)

Trace gases measurements are used to diagnose both the chemistry and transport of the atmosphere. These lectures emphasize the interpretation of trace gases measurements and techniques used to untangle chemistry and transport effects. I will discuss PV transform, trajectory techniques, and age-of-air as far as the circulation of the stratosphere.

Schoeberl, Mark R.

2005-01-01

354

ANALYSIS OF PROTOCOL GASES  

EPA Science Inventory

In 1992, EPA's Atmospheric Research and Exposure Assessment Laboratory initiated a nationwide QA program on the suppliers of EPA Protocol Gases. he program has three goals: to increase the acceptance and use of Protocol Gases by the air monitoring community, to provide a QA check...

355

Plagioclase Dissolution during CO2-SO2 Cosequestration: Effects of Sulfate.  

PubMed

Geologic CO2 sequestration (GCS) is one of the most promising methods to mitigate the adverse impacts of global climate change. The performance of GCS can be affected by mineral dissolution and precipitation induced by injected CO2. Cosequestration with acidic gas such as SO2 can reduce the high cost of GCS, but it will increase the sulfate's concentration in GCS sites, where sulfate can potentially affect plagioclase dissolution/precipitation. This work investigated the effects of 0.05 M sulfate on plagioclase (anorthite) dissolution and subsequent mineral precipitation at 90 °C, 100 atm CO2, and 1 M NaCl, conditions relevant to GCS sites. The adsorption of sulfate on anorthite, a Ca-rich plagioclase, was examined using attenuated total reflectance Fourier-transform infrared spectroscopy and then simulated using density functional theory calculations. We found that the dissolution rate of anorthite was enhanced by a factor of 1.36 by the formation of inner-sphere monodentate complexes between sulfate and the aluminum sites on anorthite surfaces. However, this effect was almost completely suppressed in the presence of 0.01 M oxalate, an organic ligand that can exist in GCS sites. Interestingly, sulfate also inhibited the formation of secondary mineral precipitation through the formation of aluminum-sulfate complexes in the aqueous phase. This work, for the first time, reports the surface complexation between sulfate and plagioclase that can occur in GCS sites. The results provide new insights for obtaining scientific guidelines for the proper amount of SO2 coinjection and finally for evaluating the economic efficiency and environmental safety of GCS operations. PMID:25549263

Min, Yujia; Kubicki, James D; Jun, Young-Shin

2015-02-01

356

40 CFR 57.205 - Submission of supplementary information upon relaxation of an SO2 SIP emission limitation.  

Code of Federal Regulations, 2010 CFR

...supplementary information upon relaxation of an SO2 SIP emission limitation...supplementary information upon relaxation of an SO2 SIP emission limitation...notification by EPA. This time limit may be extended by EPA...shall be amended within the time contemplated by §...

2010-07-01

357

PILOT-SCALE PARAMETRIC TESTING OF SPRAY DRYER SO2 SCRUBBER FOR LOW-TO-MODERATE SULFUR COAL UTILITY APPLICATIONS  

EPA Science Inventory

The report gives results of a comprehensive, pilot, dry, SO2 scrubbing test program to determine the effects of process variables on SO2 removal. In the spray dryer, stoichiometric ratio, flue gas temperature approach to adiabatic saturation, and temperature drop across the spray...

358

Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS  

NASA Astrophysics Data System (ADS)

Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of dispersed and large-scale plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). 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, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. 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.

Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Dils, B.; Corradini, S.; Merucci, L.; Coheur, P.-F.; Van Roozendael, M.; Hurtmans, D.; Clerbaux, C.; Tait, S.; Ferrucci, F.

2012-12-01

359

Volcanic SO2 fluxes derived from satellite data: a survey using OMI, GOME-2, IASI and MODIS  

NASA Astrophysics Data System (ADS)

Sulphur dioxide (SO2) fluxes of active degassing volcanoes are routinely measured with ground-based equipment to characterize and monitor volcanic activity. SO2 of unmonitored volcanoes or from explosive volcanic eruptions, can be measured with satellites. However, remote-sensing methods based on absorption spectroscopy generally provide integrated amounts of already dispersed plumes of SO2 and satellite derived flux estimates are rarely reported. Here we review a number of different techniques to derive volcanic SO2 fluxes using satellite measurements of plumes of SO2 and investigate the temporal evolution of the total emissions of SO2 for three very different volcanic events in 2011: Puyehue-Cordón Caulle (Chile), Nyamulagira (DR Congo) and Nabro (Eritrea). High spectral resolution satellite instruments operating both in the ultraviolet-visible (OMI/Aura and GOME-2/MetOp-A) and thermal infrared (IASI/MetOp-A) spectral ranges, and multispectral satellite instruments operating in the thermal infrared (MODIS/Terra-Aqua) are used. We show that satellite data can provide fluxes with a sampling of a day or less (few hours in the best case). Generally the flux results from the different methods are consistent, and we discuss the advantages and weaknesses of each technique. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables us to assess the consistency of the SO2 products from the different sensors used.

Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Dils, B.; Corradini, S.; Merucci, L.; Coheur, P.-F.; Van Roozendael, M.; Hurtmans, D.; Clerbaux, C.; Tait, S.; Ferrucci, F.

2013-06-01

360

RETROFIT COSTS FOR SO2 AND NOX CONTROL OPTIONS AT 200 COAL-FIRED PLANTS, VOLUME I - INTRODUCTION AND METHODOLOGY  

EPA Science Inventory

The report gives results of a study, the objective of which was to significantly improve engineering cost estimates currently being used to evaluate the economic effects of applying SO2 and NOx controls at 200 large SO2-emitting coal-fired utility plants. To accomplish the object...

361

DESIGN AND PERFORMANCE OF A FIELD EXPOSURE SYSTEM FOR EVALUATION OF THE ECOLOGICAL EFFECTS OF SO2 ON NATIVE GRASSLAND  

EPA Science Inventory

The report describes the design and performance of two replicate field exposure systems for evaluating the ecological effects of chronic SO2 exposure on 0.5 ha plots of native Montana grassland. The SO2 was supplied at a constant rate to each plot through a network of 2.5-cm insi...

362

CONTROLLING SO2 EMISSIONS FROM COAL-FIRED STEAM-ELECTRIC GENERATORS: WATER POLLUTION IMPACT. VOLUME I. EXECUTIVE SUMMARY  

EPA Science Inventory

The report gives results of one task in a comprehensive program to review a New Source Performance Standards (NSPS) for SO2 emissions from coal-fired steam-electric generating plants. The results compare two alternative standard to the existing NSPS (1.2 lb SO2/million Btu of hea...

363

CONTROLLING SO2 EMISSIONS FROM COAL-FIRED STEAM-ELECTRIC GENERATORS: WATER POLLUTION IMPACT. VOLUME II. TECHNICAL DISCUSSION  

EPA Science Inventory

The report gives results of one task in a comprehensive program to review the New Source Performance Standard (NSPS) for SO2 emissions from coal-fired steam-electric generating plants. The results compare two alternative standards to the existing NSPS (1.2 lb SO2/million Btu of h...

364

77 FR 15608 - Revisions to Final Response to Petition From New Jersey Regarding SO2 Emissions From the Portland...  

Federal Register 2010, 2011, 2012, 2013, 2014

...to Final Response to Petition From New Jersey Regarding SO[bdi2] Emissions From...to Final Response to Petition From New Jersey Regarding SO 2 Emissions From...to Final Response to Petition From New Jersey Regarding SO 2...

2012-03-16

365

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

Code of Federal Regulations, 2011 CFR

...and multiple stacks for SO2 emissions and heat input determinations. 75.16 Section...and multiple stacks for SO2 emissions and heat input determinations. (a) [Reserved...emissions are not underestimated. (e) Heat input rate. The owner or operator...

2011-07-01

366

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...  

Code of Federal Regulations, 2013 CFR

...and multiple stacks for SO 2 emissions and heat input determinations. 75.16 Section...multiple stacks for SO 2 emissions and heat input determinations. (a) [Reserved...emissions are not underestimated. (e) Heat input rate. The owner or operator...

2013-07-01

367

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...  

Code of Federal Regulations, 2014 CFR

...and multiple stacks for SO 2 emissions and heat input determinations. 75.16 Section...multiple stacks for SO 2 emissions and heat input determinations. (a) [Reserved...emissions are not underestimated. (e) Heat input rate. The owner or operator...

2014-07-01

368

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

Code of Federal Regulations, 2012 CFR

...and multiple stacks for SO2 emissions and heat input determinations. 75.16 Section...and multiple stacks for SO2 emissions and heat input determinations. (a) [Reserved...emissions are not underestimated. (e) Heat input rate. The owner or operator...

2012-07-01

369

Highly efficient SO2 absorption/activation and subsequent utilization by polyethylene glycol-functionalized Lewis basic ionic liquids.  

PubMed

Up to now, flue-gas desulfurization (FGD) is one of the most effective techniques to control SO(2) emission from the combustion of fossil fuels. The conventional technology for FGD poses serious inherent drawbacks such as formation of byproducts and volatilization of solvents. In this work, polyethylene glycol (PEG)-functionalized Lewis basic ionic liquids (ILs) derived from DABCO were proved to be highly efficient absorbents for FGD due to its specific features such as high thermal stability, negligible vapor pressure, high loading capacity. Notably, PEG(150)MeDABCONTf(2) gave an extremely high SO(2) capacity (4.38 mol mol(-1) IL), even under 0.1 bar SO(2) partial pressure (1.01 mol mol(-1) IL), presumably owing to the strong SO(2)-philic characterization of the PEG chain. Furthermore, the absorbed SO(2) could be easy to release by just bubbling N(2) at room temperature, greatly reducing energy requirement for SO(2) desorption. In addition, SO(2)/CO(2) selectivity (110) of PEG(150)MeDABCONTf(2) is two times larger than the non-functionalized imidazolium IL (45). On the other hand, through activation of SO(2) with the tertiary nitrogen in the cation, Lewis basic ILs such as PEG(150)MeDABCOBr proved to be efficient catalysts for the conversion of SO(2) to some value-added chemicals such as cyclic sulfites without utilization of any organic solvent or additive. Thus, this protocol would pave the way for the development of technological innovation towards efficient and low energy demanded practical process for SO(2) absorption and subsequent transformation. PMID:23090138

Yang, Zhen-Zhen; He, Liang-Nian; Song, Qing-Wen; Chen, Kai-Hong; Liu, An-Hua; Liu, Xiang-Ming

2012-12-01

370

Results of investigating gases from inclusions in lunar glasses  

NASA Technical Reports Server (NTRS)

Common gases from inclusions in glass fragments and spherules of lunar surface material returned by the Luna 16 automatic station were investigated by the adsorption volumometric method. Inclusions from eight particles were analyzed. A gas mixture from the inclusions had two- (CO2 and H2), three- (CO2, H2 and N2 + inert gases), and (H2S, SO2, and NH3), H2,N2 + inert gases, and four component (H2S, SO2, and NH3), CO2, H2, and N2 + inert gases, compositions. Hydrogen in all analyses was 10 to 95 volume percent. Diffusional exchange with the terrestrial atmosphere was absent. An unexpectedly high density of gases in the vacuoles was obtained. The initial volume of the bubbles when the vacuoles were breached even rose 2.5 times and decreased in the limits of 2.3 to 54.5 times. Various possibilities for the formation in the lunar surface material of glass fragments and spherules are discussed.

Dolgov, Y. A.; Shugurova, N. A.

1974-01-01

371

The sensitivity of global nucleation, cloud condensation nuclei and climate to SO2 and Criegee-intermediate chemistry  

NASA Astrophysics Data System (ADS)

Recent studies have shown that the reaction of stabilized Criegee intermediates (CIs, formed from the ozonolysis of alkenes) with SO2 may be an important source sulfuric acid vapor (H2SO4) in alkene-rich regions. We use a global atmospheric chemistry model, GEOS-Chem, with the online aerosol microphysics module, TOMAS, to investigate the impact of CI+SO2 chemistry on cloud condensation nuclei (CCN) concentrations. To get an upper bound for the effect of CI+SO2 chemistry, we use the fastest published rate constants in our simulations. The addition of CI+SO2 chemistry increases H2SO4 globally by 4%, but by over 100% in forested regions, particularly the tropics. However, changes in CCN due to CI+SO2 chemistry were significantly lower, less than 1% globally and no more than 15% in any region. The estimated change in the brightness aerosol indirect effect (AIE) due to the addition of CI+SO2 chemistry was-0.03 W m-2 globally, which is over an order-of-magnitude smaller than many other model uncertainties such as nucleation mechanisms, primary emissions, SOA and deposition. Thus, we conclude that the details of CI+SO2 chemistry are relatively unimportant in predicting the aerosol indirect effect and have only a minor impact on climate.

Pierce, J. R.; Evans, M. J.; Scott, C. E.; D'Andrea, S. D.; Farmer, D. K.; Swietlicki, E.; Spracklen, D. V.

2013-05-01

372

A rapid method to derive horizontal distributions of trace gases and aerosols near the surface using multi-axis differential optical absorption spectroscopy  

NASA Astrophysics Data System (ADS)

We apply a novel experimental procedure for the rapid measurement of the average volume mixing ratios (VMRs) and horizontal distributions of trace gases such as NO2, SO2, and HCHO in the boundary layer, which was recently suggested by Sinreich et al. (2013). The method is based on two-dimensional scanning multi-axis differential optical absorption spectroscopy (MAX-DOAS). It makes use of two facts (Sinreich et al., 2013): first, the light path for observations at 1° elevation angle traverses mainly air masses located close to the ground (typically < 200 m); second, the light path length can be calculated using the simultaneous measured absorption of the oxygen dimer O4. Thus, the average value of the trace gas VMR in the atmospheric layer between the surface and the particular altitude, for which this observation was sensitive, can be calculated. Compared to the originally proposed method, we introduce several important modifications and improvements: We apply the method only to measurements at 1° elevation angle (besides zenith view), for which the uncertainties of the retrieved values of the VMRs and surface extinctions are especially small. Using only 1° elevation angle for off-axis observation also allows an increased temporal resolution. We determine (and apply) correction factors (and their uncertainties) directly as function of the measured O4 absorption. Finally, the method is extended to trace gases analysed at other wavelengths and also to the retrieval of aerosol extinction. Depending on atmospheric visibility, the typical uncertainty of the results ranges from about 20% to 30%. We apply the rapid method to observations of a newly-developed ground-based multifunctional passive differential optical absorption spectroscopy (GM-DOAS) instrument in the north-west outskirts near Hefei in China. We report NO2, SO2, and HCHO VMRs and aerosol extinction for four azimuth angles and compare these results with those from simultaneous long-path DOAS observations. Good agreement is found (squares of the correlation coefficients for NO2, SO2, and HCHO were 0.92, 0.85, and 0.60, respectively), verifying the reliability of this novel method. Similar agreement is found for the comparison of the aerosol extinction with results from visibility meters. Future studies may conduct measurements using a larger number of azimuth angles to increase the spatial resolution.

Wang, Y.; Li, A.; Xie, P. H.; Wagner, T.; Chen, H.; Liu, W. Q.; Liu, J. G.

2014-06-01

373

Atomization Energies of SO and SO2; Basis Set Extrapolation Revisted  

NASA Technical Reports Server (NTRS)

The addition of tight functions to sulphur and extrapolation to the complete basis set limit are required to obtain accurate atomization energies. Six different extrapolation procedures are tried. The best atomization energies come from the series of basis sets that yield the most consistent results for all extrapolation techniques. In the variable alpha approach, alpha values larger than 4.5 or smaller than 3, appear to suggest that the extrapolation may not be reliable. It does not appear possible to determine a reliable basis set series using only the triple and quadruple zeta based sets. The scalar relativistic effects reduce the atomization of SO and SO2 by 0.34 and 0.81 kcal/mol, respectively, and clearly must be accounted for if a highly accurate atomization energy is to be computed. The magnitude of the core-valence (CV) contribution to the atomization is affected by missing diffuse valence functions. The CV contribution is much more stable if basis set superposition errors are accounted for. A similar study of SF, SF(+), and SF6 shows that the best family of basis sets varies with the nature of the S bonding.

Bauschlicher, Charles W., Jr.; Ricca, Alessandra; Arnold, James (Technical Monitor)

1998-01-01

374

Mineralization of basalts in the CO2-H2O-SO2-O2 system.  

PubMed

Sequestering carbon dioxide (CO2) containing minor amounts of co-contaminants in geologic formations was investigated in the laboratory through the use of high pressure static experiments. Five different basalt samples were immersed in water equilibrated with supercritical CO2 containing 1 wt % sulfur dioxide (SO2) and 1 wt % oxygen (O2) at reservoir conditions (? 100 bar, 90 °C) for 48 and 98 days. Gypsum (CaSO4) was a common precipitate, occurred early as elongated blades with striations, and served as substrates for other mineral products. In addition to gypsum, bimodal pulses of water released during dehydroxylation were key indicators, along with X-ray diffraction, for verifying the presence of jarosite-alunite group minerals. Well-developed pseudocubic jarosite crystals formed surface coatings, and in some instances, mixtures of natrojarosite and natroalunite aggregated into spherically shaped structures measuring 100 ?m in diameter. Reaction products were also characterized using infrared spectroscopy, which indicated OH and Fe-O stretching modes. The presences of jarosite-alunite group minerals were found in the lower wavenumber region from 700 to 400 cm(-1). A strong preferential incorporation of Fe(III) into natrojarosite was attributed to the oxidation potential of O2. Evidence of CO2 was detected during thermal decomposition of precipitates, suggesting the onset of mineral carbonation. PMID:24669947

Schaef, Herbert T; Horner, Jake A; Owen, Antoinette T; Thompson, Chris J; Loring, John S; McGrail, Bernard P

2014-05-01

375

Mineralization of Basalts in the CO2-H2O-SO2-O2 System  

SciTech Connect

Sequestering carbon dioxide (CO2) containing minor amounts of co-contaminants in geologic formations was investigated in the laboratory through the use of high pressure static experiments. Five different basalt samples were immersed in water equilibrated with supercritical CO2 containing 1wt% sulfur dioxide (SO2) and 1wt% oxygen (O2) at reservoir conditions (~100 bar, 90°C) for 49 and 98 days. Gypsum (CaSO4) was a common precipitate, occurred early as elongated blades with striations, and served as substrates for other mineral products. Bimodal pulses of water released during dehydroxylation were key indicators along with X-ray diffraction for verifying the presences of jarosite-alunite group minerals. Well-developed pseudocubic jarosite crystals formed surface coatings, and in some instances mixtures of natrojarosite and natroalunite aggregated into spherically shaped structures measuring 100 ?m in diameter. Reaction products were also characterized using infrared spectroscopy, which indicated OH and Fe-O stretching modes. The presences of jarosite-alunite group minerals were found in the lower wavenumber region from 700–400 cm-1. A strong preferential incorporation of Fe(III) into natrojarosite was attributed to the oxidation potential of O2. Evidence of CO2 was detected during thermal decomposition of precipitates, suggesting the onset of mineral carbonation.

Schaef, Herbert T.; Horner, Jacob A.; Owen, Antionette T.; Thompson, Christopher J.; Loring, John S.; McGrail, B. Peter

2014-05-01

376

History of SO2 removal system at the Meramec plant of union electric.  

PubMed

In line with the then emerging air pollution control regulations Union Electric installed a limestone injection wet scrubber sulfur dioxide removal system on an intermediate size coal-fired utility boiler at its Meramec Power Plant on an experimental basis in September, 1968. Approximately 3 years of operation many difficulties were encountered with plugging and scaling of various system components by calcium sulphate. As a result of this experience along with related experiences by other utilities employing similar systems, the experiment was terminated in June, 1971. As a result of the experiences gained, however, second generation experiments in sulfur dioxide removal have been initiated elsewhere with the hope of improved performance. A number of experimental projects are still under tests. Costs in resources, reliability, and disposal of residual by-products are matters of great concern. The ture cost of sulfur dioxide removal systems in dollars and resources is not well known and perhaps a reevaluation of current and future SO2 removal projects is in order at this time before additional resources are committed. PMID:1193027

Dreifke, G E; McLaughlin, J F; Smith, J D

1975-01-01

377

Rates of volcanic CO2 degassing from airborne determinations of So2 emission rates and plume CO2/SO2: Test study at Pu??u O??o?? cone, Kilauea volcano, Hawaii  

USGS Publications Warehouse

We present an airborne method that eliminates or minimizes several disadvantages of the customary plume cross-section sampling method for determining volcanic CO2 emission rates. A LI-COR CO2 analyzer system (LICOR), a Fourier transform infrared spectrometer system (FTIR), and a correlation spectrometer (COSPEC) were used to constrain the plume CO2/SO2 and the SO2 emission rate. The method yielded a CO2 emission rate of 300 td-1 (metric tons per day) for Pu??u O??o?? cone, Kilauea volcano, on 19 September 1995. The CO2/SO2 of 0.20 determined from airborne LICOR and FTIR plume measurements agreed with the CO2/SO2 of 204 ground-based samples collected from vents over a 14-year period since the Pu??u O??o?? eruption began in January 1983. Copyright 1998 by the American Geophysical Union.

Gerlach, T.M.; McGee, K.A.; Sutton, A.J.; Elias, T.

1998-01-01

378

SO2 and CS2 cross section data in the ultraviolet region. [Venus and Io atmospheric spectra  

NASA Technical Reports Server (NTRS)

Using synchrotron radiation as a continuum background, the cross sections of SO2 in the 208-228 and 299-340 nm region and of CS2 in the 318-350 nm region have been measured with a bandwidth of 0.06 nm. It has been confirmed that the reported band positions of SO2 in the 170-315 nm region by Warneck et al. (1964) should all be shifted by about 0.3 nm toward shorter wavelengths. An important application of the present results is found in the SO2 and CS2 mixing ratio calculations for Venus and Io.

Wu, C. Y. R.; Judge, D. L.

1981-01-01

379

Regulating Greenhouse Gases  

NSDL National Science Digital Library

This video highlights the work of climate scientists in the Amazon who research the relationship between deforestation, construction of new dams, and increased amounts of greenhouse gases being exchanged between the biosphere and the atmosphere.

KQED

380

Impact of NO2 Profile Shape in OMI Tropospheric NO2 Retrievals  

NASA Technical Reports Server (NTRS)

Nitrogen oxides (NOx NO + NO2) are key actors in air quality and climate change. Tropospheric NO2 columns from the nadir-viewing satellite sensors have been widely used to understand sources and chemistry of NOx. We have implemented several improvements to the operational algorithm developed at NASA GSFC and retrieved tropospheric NO2 columns. We present tropospheric NO2 validation studies of the new OMI Standard Product version 2.1 using ground-based and in-situ aircraft measurements. We show how vertical profile of scattering weight and a-priori NO2 profile shapes, which are taken from chemistry-transport models, affect air mass factor (AMF) and therefore tropospheric NO2 retrievals. Users can take advantage of scattering weights information that is made available in the operational NO2 product. Improved tropospheric NO2 data retrieved using thoroughly evaluated high spatial resolution NO2 profiles are helpful to test models.

Lamsal, Lok; Krotkov, Nickolay A.; Pickering, K.; Schwartz, W. H.; Celarier, E. A.; Bucsela, E. J.; Gleason, J. F.; Philip, S.; Nowlan, C.; Martin, R. V.; Irie, H.; Knepp, T. R.; He, H.; Brent, L.

2013-01-01

381

7, 50135051, 2007 NO2 from lightning  

E-print Network

#12;ACPD 7, 5013­5051, 2007 NO2 from lightning observed by OSIRIS C. E. Sioris et al. Title Page ratio. We find that lightning is the main production mechanism responsible for the large en- hancements of the NO2 enhancements are obtained by perturbing10 the lightning within the GEOS-Chem 3-dimensional

Paris-Sud XI, Université de

382

Investigating Seasonal Variability in NO2 Concentrations  

NSDL National Science Digital Library

Students will examine data in several formats in order to determine the presence or absence of seasonal variability in tropospheric nitrogen dioxide (NO2) concentrations. The dataset used in this lesson is monthly averages of NO2 as measured from NASA's EOS Aura spacecraft.

383

Laboratory studies of charged particle erosion of SO2 ice and applications to the frosts of Io  

NASA Technical Reports Server (NTRS)

The removal and/or redistribution of SO2 frosts on the surface of the first Galilean satellite, Io, can occur through the erosion of these frosts by the magnetosphere particle environment of the satellite. The energy, species, and temperature dependence of the erosion rates of SO2 ice films by charged particles have been studied in laboratory experiments. Rutherford backscattering and thin film techniques are used in the experiments. The ice temperature is varied between about 10 K and the sublimation temperature. The erosion rates are found to have a temperature-independent and a temperature-dependent regime and to be much greater, for 10-2000 keV ions, than those predicted by the usual sputtering process. The laboratory results are used together with measured magnetosphere particle fluxes in the vicinity of Io to estimate the erosion rates of SO2 ice films from the satellite and implications therefrom on an SO2 atmosphere on Io.

Lanzerotti, L. J.; Brown, W. L.; Augustyniak, W. M.; Johnson, R. E.; Armstrong, T. P.

1982-01-01

384

40 CFR 52.1923 - Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions...  

Code of Federal Regulations, 2012 CFR

...Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions; What are the FIP requirements for Units 4 and 5 of the Oklahoma Gas and Electric Muskogee plant; Units 1 and 2 of the...

2012-07-01

385

40 CFR 52.1923 - Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions...  

Code of Federal Regulations, 2013 CFR

...Best Available Retrofit Requirements (BART) for SO2 and Interstate pollutant transport provisions; What are the FIP requirements for Units 4 and 5 of the Oklahoma Gas and Electric Muskogee plant; Units 1 and 2 of the...

2013-07-01

386

Sulphur Chemistry in KOH-SO2 Activation of Fluid Coke and Mercury Adsorption from Aqueous Solutions.  

E-print Network

??The technical feasibility of producing sulphur-impregnated activated carbons (SIACs) from high-sulphur fluid coke by chemical activation was investigated. Using KOH and SO2, the activation process… (more)

Cai, Hui

2012-01-01

387

Theoretical description of functionality, applications, and limitations of SO2 cameras for the remote sensing of volcanic plumes  

NASA Astrophysics Data System (ADS)

The SO2 camera is a novel device for the remote sensing of volcanic emissions using solar radiation scattered in the atmosphere as a light source for the measurements. The method is based on measuring the ultra-violet absorption of SO2 in a narrow wavelength window around 310 nm by employing a band-pass interference filter and a 2 dimensional UV-sensitive CCD detector. The effect of aerosol scattering can in part be compensated by additionally measuring the incident radiation around 325 nm, where the absorption of SO2 is about 30 times weaker, thus rendering the method applicable to optically thin plumes. For plumes with high aerosol optical densities, collocation of an additional moderate resolution spectrometer is desirable to enable a correction of radiative transfer effects. 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 and for studying the dynamics of volcanic plumes in the atmosphere. This study gives a theoretical basis for the pertinent aspects of working with SO2 camera systems, including the measurement principle, instrument design, data evaluation and technical applicability. Several issues are identified that influence camera calibration and performance. For one, changes in the solar zenith angle lead to a variable light path length in the stratospheric ozone layer and therefore change the spectral distribution of scattered solar radiation incident at the Earth's surface. The varying spectral illumination causes a shift in the calibration of the SO2 camera's results. Secondly, the lack of spectral resolution inherent in the measurement technique leads to a non-linear relationship between measured weighted average optical density and the SO2 column density. Thirdly, as is the case with all remote sensing techniques that use scattered solar radiation as a light source, the radiative transfer between the sun and the instrument is variable, with both "radiative dilution" as well as multiple scattering occurring. These effects can lead to both, over or underestimation of the SO2 column density by more than an order of magnitude. As the accurate assessment of volcanic emissions depends on our ability to correct for these issues, recommendations for correcting the individual effects during data analysis are given. Aside from the above mentioned intrinsic effects, the particular technical design of the SO2 camera can also greatly influence its performance, depending on the setup chosen. A general description of an instrument setup is given, and the advantages and disadvantages of certain specific instrument designs are discussed. Finally, several measurement examples are shown and possibilities to combine SO2 camera measurements with other remote sensing techniques are explored.

Kern, C.; Kick, F.; Lübcke, P.; Vogel, L.; Wöhrbach, M.; Platt, U.

2010-06-01

388

Theoretical description of functionality, applications, and limitations of SO2 cameras for the remote sensing of volcanic plumes  

NASA Astrophysics Data System (ADS)

The SO2 camera is a novel technique for the remote sensing of volcanic emissions using solar radiation scattered in the atmosphere as a light source for the measurements. The method is based on measuring the ultra-violet absorption of SO2 in a narrow wavelength window around 310 nm by employing a band-pass interference filter and a 2-D UV-sensitive CCD detector. 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 and for studying the dynamics of volcanic plumes in the atmosphere. This study gives a theoretical basis for the pertinent aspects of working with SO2 camera systems, including the measurement principle, instrument design, data evaluation and technical applicability. Several issues are identified that influence camera calibration and performance. For one, changes in the solar zenith angle lead to a variable light path length in the stratospheric ozone layer and therefore change the spectral distribution of scattered solar radiation incident at the Earth's surface. The thus varying spectral illumination causes a shift in the calibration of the SO2 camera's results. Secondly, the lack of spectral resolution inherent in the measurement technique leads to a non-linear relationship between measured weighted average optical density and the SO2 column density. In addition, as is the case with all remote sensing techniques that use scattered solar radiation as a light source, the radiative transfer between the sun and the instrument is variable, with both radiative dilution as well as multiple scattering occurring. These effects can lead to both, over or underestimation of the SO2 column density by more than an order of magnitude. As the accurate assessment of volcanic emissions depends on our ability to correct for these issues, recommendations for correcting the individual effects during data analysis are given. Aside from the above mentioned intrinsic effects, the particular technical design of the SO2 camera can also greatly influence its performance, depending on the chosen setup. A general description of the instrument setup is given, and the advantages and disadvantages of certain specific instrument designs are discussed. Finally, several measurement examples are shown and possibilities to combine SO2 camera measurements with other remote sensing techniques are explored.

Kern, C.; Kick, F.; Lübcke, P.; Vogel, L.; Wöhrbach, M.; Platt, U.

2010-02-01

389

Monitoring Shipping Emissions with In-situ Measurements of Trace Gases  

NASA Astrophysics Data System (ADS)

The importance of discussions about ship emissions has grown due to the increase of commercial shipping as well as the publication of studies showing their serious effects on human health and on our environment. Especially in coastal areas and harbor cities the impact of ship emissions becomes more and more relevant. The establishment of a Sulfur Emission Controlled Area (SECA) for North Sea and Baltic Sea based on the MARPOL Annex VI protocol by the International Maritime Organization (IMO) has been a first step to control and reduce sulfur dioxide (SO2) emissions by consecutively regulating the sulfur content of fuels. To reduce nitrogen oxide (NOx) emissions from shipping, the emission of newly built engines is limited according to the year the engine is built (Tier I - III regulations). The project MeSMarT (Measurements of shipping emissions in the marine troposphere) has been established as a cooperation between the University of Bremen, the German Bundesamt für Seeschifffahrt und Hydrographie (Federal Maritime and Hydrographic Agency) and the Helmholtz-Zentrum Geesthacht to estimate the influence of ship emissions on the chemistry of the atmospheric boundary layer and to establish a monitoring system for main shipping routes. Pollution relevant trace gases SO2, NO2, NO, CO2 and O3 are measured with in-situ techniques. Within the project different measurement sites have been set up. In Wedel near Hamburg measurements have been performed in close distance to the Elbe River where ships entering the Hamburg harbor are passing by. It is shown that ship emission peaks can be associated with individual ships and how this information can possibly help to monitor the compliance of ships with SECA regulations. On the island Neuwerk the measurement station is located about 6 km south of the main shipping route through the German Bight. An outlook is given on how the method of identifying ship plumes can be transferred to the Neuwerk data and how the ship emissions influence the local marine air quality.

Kattner, Lisa; Mathieu-Üffing, Barbara; Aulinger, Armin; Burrows, John; Chirkov, Maksym; Matthias, Volker; Neumann, Daniel; Richter, Andreas; Schmolke, Stefan; Seyler, André; Theobald, Norbert; Wittrock, Folkard

2014-05-01

390

SO2-Binding Properties of Cationic ?6,?1-NCN-Pincer Arene Ruthenium Platinum Complexes: Spectroscopic and Theoretical Studies  

SciTech Connect

The SO2-binding properties of a series of ?6,?1-NCN-pincer ruthenium platinum complexes have been studied by both UV-visible spectroscopy, and theoretical calculations. When an electronwithdrawing [Ru(C5R5)]+ fragment (R = H or Me) is ?6-coordinated to the phenyl ring of the NCNpincer platinum fragment (cf. [2]+ and [3]+, see scheme 1), the characteristic orange coloration (pointing to ?1- SO2 binding to Pt) of a solution of the parent NCN-pincer platinum complex 1 in dichloromethane upon SO2-bubbling is not observed. However, when the ruthenium center is ?6- coordinated to a phenyl substituent linked in para-position to the carbon-to-platinum bond, i.e. complex [4]+, the SO2-binding property of the NCN-platinum center seems to be retained, as bubbling SO2 into a solution of the latter complex produces the characteristic orange color. We performed theoretical calculations at the MP2 level of approximation and TD-DFT studies, which enabled us to interpret the absence of color change in the case of [2]+ as an absence of coordination of SO2 to platinum. We analyze this absence or weaker SO2-coordination in dichloromethane to be a consequence of the relative electron-poorness of the platinum center in the respective ?6- ruthenium coordinated NCN-pincer platinum complexes, that leads to a lower binding energy and an elongated calculated Pt-S bond distance. We also discuss the effects of electrostatic interactions in these cationic systems, which also seems to play a destabilizing role for complex [2(SO2)]+.

Bonnet, Sylvestre A.; Van Lenthe, Joop H.; van Dam, Hubertus JJ; van Koten, Gerard; Klein Gebbink, Robertus J M

2011-03-01

391

Microbial reduction of SO 2 as a means of byproduct recovery from regenerable, dry scrubbing processes for flue gas desulfurization  

Microsoft Academic Search

Abstruct  A project is under way at the University of Tulsa to investigate the reduction of SO2 to H2S by sulfate reducing bacteria (SRB) in co-culture with mixed fermentative heterotrophs. We have previously demonstrated that\\u000a SO2 is completely reduced to H2S (contact times of 1–2 s) in cultures in which no redox poising agents were required and glucose served as the

Patrick Plumb; Kuoh H. Lee; Kerry L. Sublette

1990-01-01

392

Rapid recovery of stem increment in Norway spruce at reduced SO2 levels in the Harz Mountains, Germany.  

PubMed

Tree-ring width of Picea abies was studied along an altitudinal gradient in the Harz Mountains, Germany, in an area heavily affected by SO(2)-related forest decline in the second half of the 20th century. Spruce trees of exposed high-elevation forests had earlier been shown to have reduced radial growth at high atmospheric SO(2) levels. After the recent reduction of the SO(2) load due to clean air acts, we tested the hypothesis that stem growth recovered rapidly from the SO(2) impact. Our results from two formerly damaged high-elevation spruce stands support this hypothesis suggesting that the former SO(2)-related spruce decline was primarily due to foliar damage and not to soil acidification, as the deacidification of the (still acidic) soil would cause a slow growth response. Increasing temperatures and deposited N accumulated in the topsoil are likely additional growth-promoting factors of spruce at high elevations after the shortfall of SO(2) pollution. PMID:22361051

Hauck, Markus; Zimmermann, Jorma; Jacob, Mascha; Dulamsuren, Choimaa; Bade, Claudia; Ahrends, Bernd; Leuschner, Christoph

2012-05-01

393

Application of OMI, SCIAMACHY and GOME-2 Satellite SO2 Retrievals for Detection of Large Emission Sources  

NASA Technical Reports Server (NTRS)

Retrievals of sulfur dioxide (SO2) from space-based spectrometers are in a relatively early stage of development. Factors such as interference between ozone and SO2 in the retrieval algorithms often lead to errors in the retrieved values. Measurements from the Ozone Monitoring Instrument (OMI), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and Global Ozone Monitoring Experiment-2 (GOME-2) satellite sensors, averaged over a period of several years, were used to identify locations with elevated SO2 values and estimate their emission levels. About 30 such locations, detectable by all three sensors and linked to volcanic and anthropogenic sources, were found after applying low and high spatial frequency filtration designed to reduce noise and bias and to enhance weak signals to SO2 data from each instrument. Quantitatively, the mean amount of SO2 in the vicinity of the sources, estimated from the three instruments, is in general agreement. However, its better spatial resolution makes it possible for OMI to detect smaller sources and with additional detail as compared to the other two instruments. Over some regions of China, SCIAMACHY and GOME-2 data show mean SO2 values that are almost 1.5 times higher than those from OMI, but the suggested spatial filtration technique largely reconciles these differences.

Fioletov, V.E.; McLinden, C. A.; Krotkov, N.; Yang, K.; Loyola, D. G.; Valks, P.; Theys, N.; Van Roozendael, M.; Nowlan, C. R.; Chance, K.; Liu, X.; Lee, C.; Martin, R. V.

2013-01-01

394

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

NASA Technical Reports Server (NTRS)

Severe smog episodes over China in January 2013 received worldwide attention. This air pollution was distinguished by heavy loadings of fine particulate matter and SO2. To characterize these episodes, we employed the Ozone Mapping and Profiler Suite, Nadir Mapper (OMPS NM), an ultraviolet (UV) spectrometer flying on the Suomi National Polar-orbiting Partnership (SNPP) spacecraft since October 2011. We developed an advanced algorithm to quantify SO2 in the lower troposphere and achieved high-quality retrievals from OMPS NM, which are characterized by high precision, approx. 0.2 Dobson Units (DU; 1 DU = 2.69 x 10(exp 16) molecules/sq cm) for instantaneous field of view SO2 data and low biases (within +/-0.2 DU). Here we report SO2 retrievals and UV aerosol index data for these pollution events. The SO2 columns and the areas covered by high pollutant concentrations are quantified; the results reveal for the first time the full extent (an area of approx. 10(exp 6) sq km containing up to 60 kt of SO2) of these episodes.

Yang, Kai; Dickerson, Russell R.; Carn, Simon A.; Ge, Cui; Wang, Jun

2013-01-01

395

Contamination monitoring for ammonia, amines, and acid gases utilizing ion mobility spectroscopy (IMS)  

NASA Astrophysics Data System (ADS)

The effect of ammonia (NH3) and n-methyl pyrrolidinone (NMP) contamination on chemically amplified DUV resists is well documented. Other amines and related compounds are under suspicion as well. In addition, the concentration levels that are of concern have steadily decreased from approximately 10 ppbv down to levels as low as 0.1 ppbv. While some techniques such as ion chromotagraphy (IC) have been demonstrated to have limits of detection at these levels, the analysis times are rather long and cumbersome. This paper describes the use of IMS to perform these measurements, in a totally automated, continuous instrument. IMS is a simplified time-of-flight technique that requires no liquid reagents and has been demonstrated to be a reliable method for monitoring for ammonia and NMP in cleanrooms. This paper demonstrates the ability of the technique to monitor for amines such as dimethylamine, methylamine, methanolamine, ethanolamine, diethanolamine, butylamine and others. Detection limits of 0.1 ppbv and below are clearly demonstrated. Also discussed are methods of monitoring multiple points with a single analyzer. Ability to detect corrosive gases such as hydrogen fluoride (HF), hydrogen chloride (HCl), sulfur dioxide (SO2), sulfur trioxide (SO3), nitrogen dioxide (NO2), chlorine (Cl2), bromine (Br2), phosphoric acid (H3PO4) are also demonstrated.

Bacon, Tad; Webber, Kurt; Carpio, Ronald A.

1998-06-01

396

Reactivity of stabilized Criegee intermediates (sCIs) from isoprene and monoterpene ozonolysis toward SO2 and organic acids  

NASA Astrophysics Data System (ADS)

Oxidation processes in Earth's atmosphere are tightly connected to many environmental and human health issues and are essential drivers for biogeochemistry. Until the recent discovery of the atmospheric relevance of the reaction of stabilized Criegee intermediates (sCIs) with SO2, atmospheric oxidation processes were thought to be dominated by a few main oxidants: ozone, hydroxyl radicals (OH), nitrate radicals and, e.g. over oceans, halogen atoms such as chlorine. Here, we report results from laboratory experiments at 293 K and atmospheric pressure focusing on sCI formation from the ozonolysis of isoprene and the most abundant monoterpenes (?-pinene and limonene), and subsequent reactions of the resulting sCIs with SO2 producing sulfuric acid (H2SO4). The measured total sCI yields were (0.15 ± 0.07), (0.27 ± 0.12) and (0.58 ± 0.26) for ?-pinene, limonene and isoprene, respectively. The ratio between the rate coefficient for the sCI loss (including thermal decomposition and the reaction with water vapour) and the rate coefficient for the reaction of sCI with SO2, k(loss) /k(sCI + SO2), was determined at relative humidities of 10 and 50%. Observed values represent the average reactivity of all sCIs produced from the individual alkene used in the ozonolysis. For the monoterpene-derived sCIs, the relative rate coefficients k(loss) / k(sCI + SO2) were in the range (2.0-2.4) × 1012 molecules cm-3 and nearly independent of the relative humidity. This fact points to a minor importance of the sCI + H2O reaction in the case of the sCI arising from ?-pinene and limonene. For the isoprene sCIs, however, the ratio k(loss) / k(sCI + SO2) was strongly dependent on the relative humidity. To explore whether sCIs could have a more general role in atmospheric oxidation, we investigated as an example the reactivity of acetone oxide (sCI from the ozonolysis of 2,3-dimethyl-2-butene) toward small organic acids, i.e. formic and acetic acid. Acetone oxide was found to react faster with the organic acids than with SO2; k(sCI + acid) / k(sCI + SO2) = (2.8 ± 0.3) for formic acid, and k(sCI + acid) / k(sCI + SO2) = (3.4 ± 0.2) for acetic acid. This finding indicates that sCIs can play a role in the formation and loss of other atmospheric constituents besides SO2.

Sipilä, M.; Jokinen, T.; Berndt, T.; Richters, S.; Makkonen, R.; Donahue, N. M.; Mauldin, R. L., III; Kurtén, T.; Paasonen, P.; Sarnela, N.; Ehn, M.; Junninen, H.; Rissanen, M. P.; Thornton, J.; Stratmann, F.; Herrmann, H.; Worsnop, D. R.; Kulmala, M.; Kerminen, V.-M.; Petäjä, T.

2014-11-01

397

EFFECTS OF FLY ASH TRANSITION METAL CONTENT AND FLUE GAS HCL/SO2 RATIO ON MERCURY SPECIATION IN WASTE COMBUSTION  

EPA Science Inventory

The paper presents results of research on the effect of sulfur dioxide (SO2):HCI ratio on heterogeneous Hg0 oxidation. The addition of SO2 to moist flue gas at high SO2:HCI ratios (4:1 to 10:1) caused a decrease in oxidation of Hg0 relative to flur gas without SO2. This is attrib...

398

40 CFR 97.710 - State SO2 Group 2 trading budgets, new unit set-asides, Indian country new unit set-aside, and...  

Code of Federal Regulations, 2012 CFR

...905 tons. (vi) [Reserved] (3) Kansas. (i) The SO2 trading budget for... (3) The SO2 variability limit for Kansas is 7,475 tons. (4) The SO2 variability...and thereafter is 2,711 tons. (3) Kansas. (i) The SO2 trading budget...

2012-07-01

399

The flux of sulfur-containing gases to vegetation  

NASA Astrophysics Data System (ADS)

The flux of five sulfur gases to vegetation exposed to each gas individually at an ambient concentration of 0.12 ?l ?-1 (5 ?moles m -3) was assessed using a whole-plant, gaseous exchange system. Total leaf flux of each gas was partitioned into leaf surface (adsorption) and internal (absorption) fractions. Internal flux varied four to sevenfold among gases, and the magnitude of flux was in the following order: sulfur dioxide > hydrogen sulfide > carbonyl sulfide > methyl mercaptan > carbon disulfide. The regression of internal flux on water solubility and molecular size accounted for 73 and 87 % of the variation in Glycine max and Phaseolus vulgaris, respectively. Leaf conductance, which was adjusted for each gas based on their respective diffusivities in air, did not improve the regression significantly. Estimates of internal flux based on the product of leaf conductance and ambient concentration may not be an accurate technique to assess the rate of absorption for all pollutant gases into the leaf interior under daylight conditions. For highly soluble and chemically reactive gases such as SO 2, the latter technique tends to underestimate flux by 50%, which may result from a mean SO 2 diffusive path length that is less than that for water vapor. The relationship between flux and the physicochemical properties of a gas may provide a technique for screening atmospheric emissions for their potential toxicity to vegetation.

Taylor, G. E.; McLaughlin, S. B.; Shriner, D. S.; Selvidge, W. J.

400

Health hazards from volcanic gases: a systematic literature review.  

PubMed

Millions of people are potentially exposed to volcanic gases worldwide, and exposures may differ from those in anthropogenic air pollution. A systematic literature review found few primary studies relating to health hazards of volcanic gases. SO2 and acid aerosols from eruptions and degassing events were associated with respiratory morbidity and mortality but not childhood asthma prevalence or lung function decrements. Accumulations of H2S and CO2 from volcanic and geothermal sources have caused fatalities from asphyxiation. Chronic exposure to H2S in geothermal areas was associated with increases in nervous system and respiratory diseases. Some impacts were on a large scale, affecting several countries (e.g., Laki fissure eruption in Iceland in 1783-4). No studies on health effects of volcanic releases of halogen gases or metal vapors were located. More high quality collaborative studies involving volcanologists and epidemiologists are recommended. PMID:16789471

Hansell, Anna; Oppenheimer, Clive

2004-12-01

401

Ruby laser induced emission from NO2  

NASA Technical Reports Server (NTRS)

Two different types of emission from excited NO2 were observed using pulsed ruby laser light at 6943 A. The first type of fluorescence was seen in the near IR and results from the single photon excitation of NO2 from the ground 2-A1 state. By observing the emission as a function of time an unexpected behavior was observed in the near IR and could be explained by a consecutive deactivation mechanism, wherein a secondary species is preferentially detected. A second type of emission recently observed in the blue spectral region is weaker and is due to a multiphoton process. The intensity of the blue emission is a function of the cube of the laser intensity at low pressures and approaches the square at high pressures. This variation is attributed to simultaneous deactivation of the excited NO2 intermediate by collision (square) and by anti-Stokes Raman scattering off of the excited NO2 (cube).

Hakala, D. F.; Reeves, R. R.

1976-01-01

402

Metal oxide semiconductor NO 2 sensor  

Microsoft Academic Search

A newly developed sensor for NO2 has been investigated from a practical point of view. Various metal oxide semiconductors have been examined and as a result it is found that WO3 shows the highest potentiality as an NO2 sensor for air-quality monitoring. Several approaches, such as introducing SiO2 binder, microprocessing techniques, heat-cleaning techniques and adopting a filter material, have been

Tomohiro Inoue; Kazuyuki Ohtsuka; Yutaka Yoshida; Yoshinobu Matsuura; Yoshihisa Kajiyama

1995-01-01

403

Mechanism of Preferential Adsorption of SO2 into Two Microporous Paddle Wheel Frameworks M(bdc)(ted)(0.5)  

SciTech Connect

The adsorption of a corrosive gas, SO¬2, into microporous pillared paddle-wheel frameworks M(bdc)(ted)0.5 [M = Ni, , Zn; bdc = 1,4-benzenedicarboxylate; ted=triethylenediamine] is studied by volumetric adsorption measurements and a combination of in-situ infrared spectroscopy and ab initio density functional theory (DFT) calculations. The uptake of SO2 in M(bdc)(ted)0.5 at room temperature is quite significant, 9.966 mol kg-1(63.8%) at room temperature/1.132 bar, which represents the highest SO2 uptake so far observed. Two different adsorption species are identified by infrared spectroscopy: one is typical physisorbed SO2 species, charac-terized by a modest red shift of S-O stretching bands (36 cm-1 for ?as and 7 cm-1 for ?s); the other characterized by adsorption bands at 1242 and 1105cm-1 and by a much higher (~150?C) temperature to completely remove. Theoretical calculations including van der Waals interactions (based on vdW-DF) indicate that the adsorption geometry of SO2 involves one molecule bonding of its sulfur atom to the oxygen atom of the paddle-wheel building unit and its two oxygen atoms to the C-H groups of the organic linkers by formation of hydrogen bonds. Such a configuration results in a large distortion of benzene rings, which is consistent with the experimentally observed shift of the ring deformation mode. The simulated frequency shift of the SO2 stretching bands by vdW-DF is in excellent agreement with spectroscopically measured value of physisorbed SO2. The IR absorptions at 1242 and 1105 cm-1 also suggest a stronger adsorption configuration, previously observed in SO4-like species involving two oxygen atoms of the paddle wheel building units. The adsorption configurations of SO2 into M(bdc)(ted)0.5 derived by infrared spectroscopy and vdW-DF calculations provide the understanding necessary to develop industrial processes for SO2 removal using microporous paddle-wheel frameworks materials.

Tan, Kui; Canepa, Pieremanuele; Gong, Qihan; Liu, Jian; Johnson, Daniel H.; Dyevoich, Allison A.; Thallapally, Praveen K.; Thonhauser, Timo; Li, Jing; Chabal, Y. J.

2013-12-02

404

Reactivity of stabilized Criegee intermediates (sCI) from isoprene and monoterpene ozonolysis toward SO2 and organic acids  

NASA Astrophysics Data System (ADS)

Oxidation processes in Earth's atmosphere are tightly connected to many environmental and human health issues and are essential drivers for biogeochemistry. Until the recent discovery of the atmospheric relevance of stabilized Criegee intermediates (sCI), atmospheric oxidation processes were thought to be dominated by few main oxidants: ozone, hydroxyl radicals (OH), nitrate radicals and, e.g. over oceans, halogen atoms such as chlorine. Here, we report results from laboratory experiments at 293 K and atmospheric pressure focusing on sCI formation from the ozonolysis of isoprene and the most abundant monoterpenes (?-pinene and limonene), and subsequent reactions of the resulting sCIs with SO2 producing sulphuric acid (H2SO4). The measured sCI yields were (0.15 ± 0.07), (0.27 ± 0.12) and (0.58 ± 0.26) for the ozonolysis of ?-pinene, limonene and isoprene, respectively. The ratio between the rate coefficient for the sCI loss (including thermal decomposition and the reaction with water vapour) and the rate coefficient for the reaction of sCI with SO2, k(loss) / k(sCI + SO2), was determined at relative humidities of 10% and 50%. Observed values represent the average reactivity of all sCIs produced from the individual alkene used in the ozonolysis. For the monoterpene derived sCIs, the relative rate coefficients k(loss) / k(sCI + SO2) were in the range (2.0-2.4) × 1012 molecule cm-3 and nearly independent on the relative humidity. This fact points to a minor importance of the sCI + H2O reaction in the case of the sCI arising from ?-pinene and limonene. For the isoprene sCIs, however, the ratio k(loss) / k(sCI + SO2) was strongly dependent on the relative humidity. To explore whether sCIs could have a more general role in atmospheric oxidation, we investigated as an example the reactivity of acetone oxide (sCI from the ozonolysis of 2,3-dimethyl-2-butene) toward small organic acids, i.e. formic and acetic acid. Acetone oxide was found to react faster with the organic acids than with SO2; k(sCI + acid) / k(sCI + SO2) = (2.8 ± 0.3) for formic acid and k(sCI + acid) / k(sCI + SO2) = (3.4 ± 0.2) for acetic acid. This finding suggests that sCIs can play a role in the formation and loss of several atmospheric constituents besides SO2.

Sipilä, M.; Jokinen, T.; Berndt, T.; Richters, S.; Makkonen, R.; Donahue, N. M.; Mauldin, R. L., III; Kurten, T.; Paasonen, P.; Sarnela, N.; Ehn, M.; Junninen, H.; Rissanen, M. P.; Thornton, J.; Stratmann, F.; Herrmann, H.; Worsnop, D. R.; Kulmala, M.; Kerminen, V.-M.; Petäjä, T.

2014-01-01

405

Development of a Tunable Laser Spectroscopic Method for Determining Multiple Sulfur Isotope Composition of Nanomoles of SO2  

NASA Astrophysics Data System (ADS)

Multiple sulfur isotope (32S, 33S, 34S, 36S) analyses of geological material provide important constraints on the sulfur cycles on Earth [1] and other planetary bodies, e.g., Mars [2]. However, most current multiple sulfur isotope measurements are performed on magnetic sector isotope ratio mass spectrometers (IRMS) and thus require relatively large sample size (usually about several micromoles of sulfur, except the MC-ICPMS and SIMS methods) and time-consuming sample preparation procedures. More importantly, these IRMS methods demand relatively sophisticated instrumentation, and are not ideal for field measurements or flight missions. In contrast, laser spectroscopic methods provide opportunities for significantly reducing the sample size requirement and enabling real-time monitoring in the field, and have been proven to be of great importance in the isotopic measurements of many molecules in nature, e.g. CO2, H2O, N2O, CH4. Based on a prototype built for measuring ?34S of SO2 [3], we're developing a new tunable laser spectrometer (TLS) for simultaneously determining the ?34S and ?33S of nanomoles of pure SO2. We have identified a new spectral window (<1 cm-1 wide) suitable for measuring 32SO2, 33SO2, 34SO2 simultaneously. Ongoing work focuses on increasing the optical path length of the analysis cell and determining the optimal analytical conditions, with the goal of achieving ?0.5‰ precision in both ?34S and ?33S over 30 seconds of analysis duration of ~20 nmol of pure SO2. Progress of these developments and comparison with conventional IRMS methods will be presented at the meeting. As a case study, we will also present preliminary TLS results from laboratory low pressure SO2 UV photolysis experiments where ?34S and ?33S of the residual SO2 are expected to decrease as the photolysis proceeds [4]. Future developments of this method will involve the coupling of a sample introduction system to enable multiple sulfur isotope analysis of samples other than pure SO2 [3]. [1] Johnston (2011) Earth Sci. Rev. 106, 161-183; [2] Farquhar et al. (2000) Nature. 404, 50-52; [3] Christensen et al. (2007) Anal. Chem. 79, 9261-9268; [4] Guo et al. (2010) Geochim. Cosmochim. Acta. 74, A366.

Guo, W.; Christensen, L. E.

2013-12-01

406

Gases: Characteristics and Properties  

NSDL National Science Digital Library

The first site related to ideal gas, called Ideal and Real Gas Laws, is maintained by Liina Ladon of Townsen University (1). Visitors can read about the properties of ideal gases, what the ideal gas law is, how to use it, and much more. The next site, titled Gas Laws, (2) is offered by the Ohio State University Department of Chemistry. This interactive site contains Shockwave movies of animations and audio files that describe what a gas is, the Ideal Gas Law equation, mixtures of gases, and problems using the ideal gas law. The University of Oregon site, Virtual Laboratory, teaches about the ideal gas law on the Welcome to the Pressure Chamber page (3). Those who enjoy online interaction will enjoy being able to control the action of a piston in a pressure chamber to see how the gases inside react. The fourth site includes another fun multimedia activity related to ideal gases provided by the Department of Physics and Astronomy at Western Washington University. The Air Filled Balloon in Liquid Nitrogen (4) movie shows an actual experiment of the effects on a balloon that's covered with liquid nitrogen. The page contains some additional information on the science behind the observations. The next site, called Ideal Gas Equations (5) is an online calculator that's part of Kean University's Department of Geology and Meteorology Web site. Users can calculate the pressure, volume, or temperature of a gas by inputting known variables into the various forms. Several methods and variations of calculating the values are provided as well as brief instructions. The next page from North Carolina State University's Basic Concepts in Environmental Science Web site is called Characteristics of Gases (6). Part of a larger learning module, the lesson plans objective is to use the ideal gas law to determine gas volumes at different absolute temperatures and absolute pressures. Everything needed to conduct the activity is provided including links to a volume calculator and practice problems. The seventh site is another animation that illustrates how gases react, called Molecular Model for an Ideal Gas (7). By changing the number of molecules in the chamber, their velocity, and the pressure and width of the container, users get to see how the molecules react to the conditions. The last site, Gases and Their Properties, is maintained by the Electronic Teaching Assistance Program(8). Students learn about the history of gas science, how gas laws describe ideal gases, what Dalton's Law and Graham's Law are, and much more.

Brieske, Joel A.

407

Exploring Io's Atmospheric Composition with APEX: First Measurement of 34SO2 and Tentative Detection of KCl  

NASA Astrophysics Data System (ADS)

The composition of Io's tenuous atmosphere is poorly constrained. Only the major species SO2 and a handful of minor species have been positively identified, but a variety of other molecular species should be present, based on thermochemical equilibrium models of volcanic gas chemistry and the composition of Io's environment. This paper focuses on the spectral search for expected yet undetected molecular species (KCl, SiO, S2O) and isotopes (34SO2). We analyze a disk-averaged spectrum of a potentially line-rich spectral window around 345 GHz, obtained in 2010 at the APEX 12 m antenna. Using different models assuming either extended atmospheric distributions or a purely volcanically sustained atmosphere, we tentatively measure the KCl relative abundance with respect to SO2 and derive a range of 4 × 10-4-8 × 10-3. We do not detect SiO or S2O and present new upper limits on their abundances. We also present the first measurement of the 34S/32S isotopic ratio in gas phase on Io, which appears to be twice as high as the Earth and interstellar medium reference values. Strong lines of SO2 and SO are also analyzed to check for longitudinal variations of column density and relative abundance. Our models show that, based on their predicted relative abundance with respect to SO2 in volcanic plumes, both the tentative KCl detection and SiO upper limit are compatible with a purely volcanic origin for these species.

Moullet, A.; Lellouch, E.; Moreno, R.; Gurwell, M.; Black, J. H.; Butler, B.

2013-10-01

408

Mechanism of the Gaseous Hydrolysis Reaction of SO2: Effects of NH3 versus H2O.  

PubMed

Effects of ammonia and water molecules on the hydrolysis of sulfur dioxide are investigated by theoretical calculations of two series of the molecular clusters SO2-(H2O)n (n = 1-5) and SO2-(H2O)n-NH3 (n = 1-3). The reaction in pure water clusters is thermodynamically unfavorable. The additional water in the clusters reduces the energy barrier for the reaction, and the effect of each water decreases with the increasing number of water molecules in the clusters. There is a considerable energy barrier for reaction in SO2-(H2O)5, 5.69 kcal/mol. With ammonia included in the cluster, SO2-(H2O)n-NH3, the energy barrier is dramatically reduced, to 1.89 kcal/mol with n = 3, and the corresponding product of hydrated ammonium bisulfate NH4HSO3-(H2O)2 is also stabilized thermodynamically. The present study shows that ammonia has larger kinetic and thermodynamic effects than water in promoting the hydrolysis reaction of SO2 in small clusters favorable in the atmosphere. PMID:25495573

Liu, Jingjing; Fang, Sheng; Liu, Wei; Wang, Meiyan; Tao, Fu-Ming; Liu, Jing-Yao

2015-01-01

409

Changes in membrane lipid and free fatty acid composition during low temperature preconditioning against SO2 injury in coleus.  

PubMed

The effects of a low temperature (13 degrees C) treatment known to provide protection against sulphur dioxide (SO2) injury were assessed on leaf lipid composition in two cultivars of Coleus blumei Benth, found previously to differ in sensitivity to SO2 and other environmental stresses. After 5 days growth at 13 degrees C, there were significant differences in membrane lipid fatty acid composition as well as in free fatty acid (FFA) levels between SO2-sensitive 'Buckley Supreme' ('BS') and SO2-insensitive 'Marty' ('M'). Molecular species of chloroplast galactolipids in 'M' contained increased levels of linolenic acid (18:3). In the leaf FFA pools, the saturated components, palmitic (16:0) and stearic (18:0) acids, were predominant at 20 degrees C. After temperature hardening at 13 degrees C, the total amount of FFAs decreased in 'M' but increased in 'BS.' These modifications in lipid composition suggest an additional mechanism for cultivar differences in tolerance to SO2 and other stressors in coleus. PMID:11551549

Norman, H A; Krizek, D T; Mirecki, R M

2001-09-01

410

The effect of hydrogen peroxide solution on SO2 removal in the semidry flue gas desulfurization process.  

PubMed

The present study attempts to use hydrogen peroxide solution to humidify Ca(OH)(2) particles to enhance the absorption of SO(2) to achieve higher removal efficiency and to solve the valuable reuse of the reaction product in the semidry flue gas desulfurization (FGD) process. Experiments were carried out to examine the effect of various operating parameters including hydrogen peroxide solution concentration, Ca/S molar ratio and approach to adiabatic saturation temperature on SO(2) removal efficiency in a laboratory scale spray reactor. The product samples were analyzed to obtain semi-quantitative measures of mineralogical composition by X-ray diffraction (XRD) with reference intensity ratio (RIR) method and the morphology of the samples was examined by scanning electron microscope (SEM). Compared with spraying water to humidify Ca(OH)(2), SO(2) removal efficiency was improved significantly by spraying hydrogen peroxide solution of 1-3 wt.% to humidify Ca(OH)(2) because hydrogen peroxide solution enhanced the dissolution and absorption rate of SO(2). Moreover, XRD and SEM analyses show that the desulfurization products contain less amount of unreacted Ca(OH)(2) and more amount of stable calcium sulfate with increasing hydrogen peroxide solution concentration. Thus, the process mechanism of the enhanced absorption of SO(2) by spraying hydrogen peroxide solution to humidify Ca(OH)(2) was elucidated on the basis of the experimental results. PMID:19464108

Zhou, Yuegui; Zhu, Xian; Peng, Jun; Liu, Yaobin; Zhang, Dingwang; Zhang, Mingchuan

2009-10-15

411

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.  

PubMed

An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2 from by-products was summarized. Results showed that the SO2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900-1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO2 as well as MgO, a temperature range of 900-927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries. PMID:25371652

Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang

2014-11-01

412

Selection of best impregnated palm shell activated carbon (PSAC) for simultaneous removal of SO2 and NOx.  

PubMed

This work examines the impregnated carbon-based sorbents for simultaneous removal of SO(2) and NOx from simulated flue gas. The carbon-based sorbents were prepared using palm shell activated carbon (PSAC) impregnated with several metal oxides (Ni, V, Fe and Ce). The removal of SO(2) and NOx from the simulated flue gas was investigated in a fixed-bed reactor. The results showed that PSAC impregnated with CeO(2) (PSAC-Ce) reported the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NOx. PSAC-Ce showed the longest breakthrough time of 165 and 115 min for SO(2) and NOx, respectively. The properties of the pure and impregnated PSAC were analyzed by BET, FTIR and XRF. The physical-chemical features of the PSAC-Ce sorb