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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

Improved algorithms of differential optical absorption spectroscopy for monitoring SO2, NO2 from flue gas  

NASA Astrophysics Data System (ADS)

Valuable achievements in differential optical absorption spectroscopy (DOAS) for monitoring atmospheric trace gas have been made in the past decades. However, in flue gas monitoring, it is difficult to monitor the pollutant gases at low optical density. In this paper, two improved inversion algorithms based on the genetic algorithm and Kalman filter, respectively, were developed to accurately calculate the concentrations of SO2 and NO2 from flue gas. Experimental results show that the improved algorithms have the detection limit of 10 ppm and have a zero drift of 1 ppm at a light path length of 0.5 m. Additionally, the improved algorithms of DOAS combined with the traditional DOAS algorithm can broaden the measurement range of pollutant gases by appropriately setting critical values for the maximum value of the differential optical density.

Guanghua, Tang; Chuanlong, Xu; Litang, Shao; Bin, Zhou; Daoye, Yang; Qi, Pan; Shimin, Wang

2009-01-01

4

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

5

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

NASA Astrophysics Data System (ADS)

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

Elkiey, T.; Ormrod, D. P.

6

Oxidation of SO2 by NO2 and O3 on carbon - Implications to tropospheric chemistry  

NASA Technical Reports Server (NTRS)

The oxidation of SO2 to sulfate in air at 65 percent relative humidity on carbon particles was investigated gravimetrically in the presence of NO2 and O3. Approximately 1 mg samples of carbon black were exposed to continuously flowing ppbv mixtures of SO2, SO2 + NO2 and SO2 + O3 for prescribed periods of time before desorption into dry N2. Wet chemical analysis of the particles followed desorption. NO2 and O3 were found to have little, if any, effect relative to air on sulfate yields at the concentrations studied.

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

1984-01-01

7

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

PubMed

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

Mallik, C; Lal, S

2014-02-01

8

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

9

Carbon catalyzed SO2 oxidation by NO2 and O3  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

10

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

NASA Astrophysics Data System (ADS)

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

Behera, Sailesh N.; Sharma, Mukesh

2011-08-01

11

SO2 Removal from Flue Gases Using Utility Synthesized Zeolites.  

National Technical Information Service (NTIS)

Historically, sulfur dioxide (SO2) 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 ...

M. Grutzeck

1997-01-01

12

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

13

Carbon-catalyzed oxidation of SO2 by NO2 and air  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

14

REMOVAL OF SO2 FROM INDUSTRIAL WASTE GASES  

EPA Science Inventory

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

15

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

Code of Federal Regulations, 2010 CFR

...EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods...for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2...

2010-07-01

16

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

Code of Federal Regulations, 2011 CFR

...EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods...for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2...

2011-07-01

17

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

Code of Federal Regulations, 2013 CFR

...EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods...for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2...

2013-07-01

18

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

Code of Federal Regulations, 2012 CFR

...EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods...for SO2 , CO, O3 , and NO2 . (a) Comparability. Comparability is shown for SO2 , CO, O3 , and NO2...

2012-07-01

19

The enhanced oxidation of SO2 by NO2 on carbon particulates  

NASA Technical Reports Server (NTRS)

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

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

1980-01-01

20

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

NASA Astrophysics Data System (ADS)

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

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

21

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

22

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

23

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

24

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

E-print Network

- 1 - Modifications of Phleum pratense grass pollen allergens following artificial exposure: Air pollution and pollen allergens. Key words: traffic-related pollution, grass pollen, allergen, two pollutants on grass pollen allergens. Methods: Timothy grass pollen was exposed to O3, NO2, SO2 alone

Paris-Sud XI, Université de

25

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

EPA Science Inventory

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

26

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

EPA Science Inventory

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

27

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

28

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

29

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

NASA Astrophysics Data System (ADS)

Satellite remote sensing is increasingly being used to monitor air quality over localized sources such as the Canadian oil sands. Following an initial study, significant low biases have been identified in current NO2 and SO2 retrieval products from the Ozone Monitoring instrument (OMI) satellite sensor over this location resulting from a combination of its rapid development and small spatial scale. Air mass factors (AMFs) used to convert line-of-sight "slant" columns to vertical columns were re-calculated for this region based on updated and higher resolution input information including absorber profiles from a regional scale (15 km × 15 km resolution) air quality (AQ) model, higher spatial and temporal resolution surface reflectivity, and an improved treatment of snow. The overall impact of these new Environment Canada (EC) AMFs led to substantial increases in the peak NO2 and SO2 average vertical column density (VCD), occurring over an area of intensive surface mining, by factors of 2 and 1.4, respectively, relative to estimates made with previous AMFs. Comparisons are made with long-term averages of NO2 and SO2 from in-situ surface monitors by using the AQ model to map the OMI VCDs to surface concentrations. This new OMI-EC product is able to capture the spatial distribution of the in-situ instruments (slopes of 0.7 to 1.0; correlation coefficients of 0.9). The concentration absolute values from surface network observations were in reasonable agreement, with OMI-EC NO2 and SO2 biased low by roughly 30%. Several complications were addressed including correction for the interference effect in the surface NO2 instruments and smoothing and clear-sky biases in the OMI measurements. Overall these results highlight the importance of using input information that accounts for the spatial and temporal variability of the location of interest when performing retrievals.

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

2013-08-01

30

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

31

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

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

32

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

33

Ultraviolet Absorption Spectroscopy Measurement of Trace NH3 in Gases Containing High Concentration of SO2  

NASA Astrophysics Data System (ADS)

In heavy oil-burning thermal power plants, NH3 injection is frequently used to neutralize SOx in flue gas. In order to ascertain the neutralization effect the concentration of NH3 must be measured in the presence of high concentration of SO2. Ultraviolet absorption spectroscopy in the 200-225 nm wavelength region is the most sensitive method to measure SO2 and NH3. However, as the absorption bands of SO2 and NH3 overlap, accurate determination of the SO2 absorption is needed to detect the absorption due to trace NH3. The nonlinear dependence of the absorption coefficient on the concentration, which appeared for absorption coefficients of ?>0.05 cm-1, is taken into account using a third order polynomial approximation in order to accurately determine the SO2 absorption. An analysis procedure based on this approximation was developed. Results showed that NH3 concentrations of about 4 ppm can be detected in the presence of SO2 concentrations of about 1000 ppm.

Fukuchi, Tetsuo; Ninomiya, Hideki

34

Effects of SO2 and\\/or NO2 on Native Plants of the Mojave Desert and Eastern Mojave-Colorado Desert  

Microsoft Academic Search

Ten species of plants, five perennials and five annuals, native to the Mojave desert were grown in pots and fumigated in open top plastic greenhouses, 25 hours\\/week, with SO2 and\\/or NO2. Three levels of SO2: 2.0, 0.67, and 0.22 parts per million (ppm); three levels of NO2: 1.0, 0.33, and 0.11 ppm; three treatments with 2.0 ppm SO2 + 1.0

C. Ray Thompson; Gerrit Kats; R. W. Lennox

1980-01-01

35

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

PubMed

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

Rubio, B; Izquierdo, M T

2010-07-01

36

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

NASA Astrophysics Data System (ADS)

The generalized mathematical model has been developed for radiation induced removal of NO and SO 2 from flue gases of power plants. This model includes energy absorption of electron beam with active species generation, reactions in gas phase, aerosol formation and growth, and liquid-phase chemistry. To investigate the role of various process parameters (initial NO and SO 2 concentrations, temperature, humidity, absorbed dose) a number of numerical calculations has been carried out. Computer modeling results are in good agreement with reported experimental data.

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

1996-12-01

37

Quantitative observation of boundary-layer NO2/SO2 from total-column measurements. New possibilities for space-based observations?  

NASA Astrophysics Data System (ADS)

NO2 and SO2 are criteria pollutants that play key roles in the formation of O3 and particulate matter. NO2 is significantly associated with mortality, has far reaching effects on crop yield/photosynthesis (Fishman et al. 2010), atmospheric oxidative capacity, and radiation balance either directly or via its role in ozone/radical chemistry. Major sources of NOx (NO + NO2) and SO2 include motor vehicles, power plants, fossil fuel combustion, burning biomass fuel, and natural sources (e.g. wildfires and volcanoes). GEO-CAPE (Geostationary Coastal and Air Pollution Events mission) will be in a geo-stationary orbit over the United States with improved resolution allowing observation of hourly city-scale emissions. However, estimation of surface NO2/SO2 from total-column data is complicated due to meteorological dynamics and dimensional incongruities. NASA's Chemistry And Physics of the Atmospheric Boundary Layer Experiment (CAPABLE; Langley Research Center, Hampton VA) was established to improve our understanding of these relationships. Collocated at CAPABLE are a direct-sun spectrometer (Pandora), which has previously been shown to have good agreement with OMI's NO2 retrieval, from which column NO2 and SO2 are retrieved with two-minute resolution, and surface NO2/SO2 instruments. Using the EDAS40 model for mixed-depth height we present a methodology for estimating surface NO2 from column observations that accounts for approximately 75% of the variability. Furthermore, Pandora is capable of detecting SO2 emissions from a small power plant approximately 10km NNE of the site, while OMI consistently detects no change in its corresponding pixel. Herein we present our methodology and discuss its applicability to future remote sensing missions and space-based emissions monitoring/regulation.

Knepp, T.; Pippin, M. R.; Cowen, L.; Murray, J.; Fishman, J.; Neil, D. O.; Martin, R.; Sorkin, A.; Jennings, T.; Szykamn, J.; Martins, D. K.; Thompson, A. M.; Stauffer, R. M.; Herman, J. R.; Cede, A.; Abuhassan, N.

2011-12-01

38

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

39

Removal of SO2 from simulated flue gases using non-thermal plasma-based microgap discharge.  

PubMed

The removal of sulfur dioxide (SO2) from simulated flue gases streams (N2/O2/H2O/SO2) was experimentally investigated using microgap discharge. In the experiment, the thinner dielectric layers of aluminum oxide (Al2O3) were used to form the microgap discharge. With this physical method, a high concentration of hydroxyl (OH*) radicals were produced using the ionization of O2 and H2O to further the conversion of SO2 into sulfuric acid (H2SO4) at 120 degrees C in the absence of any catalysts and absorbents, which were captured with the electrostatic precipitator (ESP). As a result, the increase of discharge power and concentrations of O2 and H2O increased the production of OH. radicals resulting in enhanced removal of SO2 from gas streams. With the test and analysis, a number of H2SO4 droplets were produced in experiment. Therefore, a new method for removal of SO2 in semidry method without ammonia (NH3) additive was found. PMID:16805405

Zhang, Zhitao; Bai, Mindong; Bai, Mindi; Bai, Xiyao; Pan, Qiaoyuan

2006-06-01

40

Air Pollution Grant Ideas Possible air pollutants to study: SO2, H2S, NO2, NH3, CO, CO2, O3.  

E-print Network

Air Pollution Grant Ideas Possible air pollutants to study: SO2, H2S, NO2, NH3, CO, CO2, O3 to the formation of ground-level ozone, and fine particle pollution, NO2 is linked with a number of adverse effects) not currently easy to find and buy in USA, simple plastic tube, cap and steel mesh. (ii) Chemical education side

Short, Daniel

41

MOF stability and gas adsorption as a function of exposure to water, humid air, SO2, and NO2  

E-print Network

Separation High-throughput Acid gas a b s t r a c t Gas adsorption and stability to liquid water, humid air, and acid gasses on metal organic frameworks have been studied using a high-throughput adsorption selectivities, (8­12), than the other MOFs ($4), mainly due to high CO2 adsorption. Long term (5 days) NO2

Nair, Sankar

42

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

43

Boundary layer measurements of the OH radical in the vicinity of an isolated power plant plume - SO2 and NO2 chemical conversion times  

NASA Technical Reports Server (NTRS)

Direct measurements of the OH radical in the vicinity of an isolated power plant plume are reported. These measurements were used to estimate the conversion time of SO2 to H2SO4-sulfate aerosol via the initiating step OH + SO2 + M yields HSO3. Using the near-high-noon measured value of OH (9.5 million per cu cm), resulted in a 1/e conversion time of 1.4 days. The latter lifetime would correspond to a conversion rate of about 2%/hr. When the lifetime calculation was modified to take into consideration the OH diurnal cycle, the 1/e conversion time for SO2 was found to be 4.4 days, giving an apparent overall rate of conversion of about 0.7%/hr. Similar calculations carried out for the conversion of NO2 to NHO3 resulted in 1/e lifetimes for NO2 of 2-3 h for midday time periods.

Davis, D. D.; Philen, D.; Mcgee, T.; Heaps, W.

1979-01-01

44

The influence of O3, NO2 and SO2 on growth of Picea abies and Fagus sylvatica in the Carpathian Mountains  

E-print Network

the combined effect of O3, NO2 and SO2 was negatively correlated with both P. abies and F. sylvatica growth specific effects of pollutants, to identify parti- cular episodes of pollution events, and to examine-term effects of air pollution. Abstract At 17 long-term pollution monitoring sites throughout the Carpathian

Liebhold, Andrew

45

Tropospheric O3, NO2, SO2, HCHO, and CHOCHO from UV/Visible Spectroscopic Measurements: Capabilities and Requirements for Geostationary Pollution Monitoring (Invited)  

NASA Astrophysics Data System (ADS)

In recent years, beginning in 1985, we have developed spaceborne spectrometers capable of measuring the minimal suite of tropospheric polluting gases considered here plus, of course, aerosols and clouds. SCIAMACHY, the GOME instruments, and OMI are all capable of making such measurements, although with limited spatial and spectral sampling. What has been required to do so are stable instruments of moderate spectral resolution (0.2-0.5 nm) and excellent noise performance, covering at least 300-460 nm (the upcoming U.S. OMPS instruments will measure part of the suite of pollutant gases). It has also been necessary to develop the underlying algorithm physics for dynamic in-orbit wavelength and slit function calibrations, Ring effect (Raman scattering) correction, spectral undersampling correction, and improved reference spectra (HITRAN), in order to properly analyze spectra. Final results depend also on accurate fitting techniques, radiative transfer modeling and chemistry and transport modeling. All of these have been developed to the point where low-Earth-orbit measurements are mature, and the capabilities are ripe for application to geostationary (or other geosynchronous) orbits, in order to measure pollution at high temporal and spatial resolution. This talk will demonstrate that the instrumental and algorithmic capabilities we have already developed can be applied directly to geostationary measurements to obtain excellent sensitivities to tropospheric O3, NO2, SO2, HCHO, and CHOCHO (and several other species which are not primary pollutants) with modest requirements for light-collecting capability. The current state of sensitivity, spatial, and temporal requirements for measurements will be discussed. These requirements lead to the instrument requirements: A scalable instrument concept which has been incrementally developed from the measurement requirements, quantitative radiative transfer modeling and fitting studies, and the capabilities we have developed for GOME, SCIAMACHY, OMI, and OMPS will be presented. Orbital considerations, especially relevant to European geosynchronous measurements, will be presented. Finally, the two outstanding needs will be discussed: (1) improved scientific requirements (e.g., providing traceability for AQ forecast improvement and other uses; (2) instrument optical and spectrograph design, including fully-informed choice of detector type.

Chance, K.; Kurosu, T. P.; Liu, X.; Newchurch, M.

2009-12-01

46

Tula industrial complex (Mexico) emissions of SO2 and NO2 during the MCMA 2006 field campaign using a Mini-DOAS system  

NASA Astrophysics Data System (ADS)

The Mexico City Metropolitan Area (MCMA) has presented severe pollution problems for many years. There are several point and mobile emission sources inside and outside the MCMA which are known to affect air quality in the area. In particular, speculation has risen as to whether the Tula industrial complex, located 60 km northwest of the MCMA has any influence on high SO2 levels occurring on the northern part of the city, in the winter season mainly. As part of the MILAGRO Field Campaign, from 24 March to 17 April 2006, the total columns of sulfur dioxide (SO2) and nitrogen dioxide (NO2) were measured during plume transects in the neighborhood of the Tula industrial complex using mini-DOAS instruments. Vertical profiles of wind speed and direction obtained from pilot balloons and radiosondes were used to calculate SO2 and NO2 fluxes in the plume. According to our measurements, calculated average flux emission for SO2 and NO2 were 155 ± 120 and 9 ± 8 ktons per year, respectively. The standard deviation of these estimations is due to actual variations in the observed emissions from the refinery and power plant, as well as to the uncertainty in the wind fields at the exact time of the measurements. These values are in good agreement with available datasets and with simulated plumes.

Rivera, C.; Sosa-Iglesias, G.; Wöhrnschimmel, H.; de Foy, B.; Johansson, M.; Galle, B.

2009-04-01

47

Tula industrial complex (Mexico) emissions of SO2 and NO2 during the MCMA 2006 field campaign using a mobile mini-DOAS system  

NASA Astrophysics Data System (ADS)

The Mexico City Metropolitan Area (MCMA) has presented severe pollution problems for many years. There are several point and mobile emission sources inside and outside the MCMA which are known to affect air quality in the area. In particular, speculation has risen as to whether the Tula industrial complex, located 60 km northwest of the MCMA has any influence on high SO2 levels occurring on the northern part of the city, in the winter season mainly. As part of the MILAGRO Field Campaign, from 24 March to 17 April 2006, the differential vertical columns of sulfur dioxide (SO2) and nitrogen dioxide (NO2) were measured during plume transects in the neighborhood of the Tula industrial complex using mobile mini-DOAS instruments. Vertical profiles of wind speed and direction obtained from pilot balloons and radiosondes were used to calculate SO2 and NO2 emissions. According to our measurements, calculated average emissions of SO2 and NO2 during the field campaign were 384±103 and 24±7 tons day-1, respectively. The standard deviation of these estimations is due to actual variations in the observed emissions from the refinery and power plant, as well as to the uncertainty in the wind fields at the exact time of the measurements. Reported values in recent inventories were found to be in good agreement with calculated emissions during the field campaign. Our measurements were also found to be in good agreement with simulated plumes.

Rivera, C.; Sosa, G.; Wöhrnschimmel, H.; de Foy, B.; Johansson, M.; Galle, B.

2009-09-01

48

Tula industrial complex (Mexico) emissions of SO2 and NO2 during the MCMA 2006 field campaign using a Mini-DOAS system  

NASA Astrophysics Data System (ADS)

The Mexico City Metropolitan Area (MCMA) has presented severe pollution problems for many years. There are several point and mobile emission sources inside and outside the MCMA which are known to affect air quality in the area. In particular, speculation has risen as to whether the Tula industrial complex, located 60 km northwest of the MCMA has any influence on high SO2 levels occurring on the northern part of the city, in the winter season mainly. As part of the MILAGRO Field Campaign, from 24 March to 17 April 2006, the total columns of sulfur dioxide (SO2) and nitrogen dioxide (NO2) were measured during plume transects in the neighborhood of the Tula industrial complex using mini-DOAS instruments. Vertical profiles of wind speed and direction obtained from pilot balloons and radiosondes were used to calculate SO2 and NO2 fluxes in the plume. According to our measurements, calculated average flux emission for SO2 and NO2 were 155±120 and 9±8 ktons per year, respectively. The standard deviation of these estimations is due to actual variations in the observed emissions from the refinery and power plant, as well as to the uncertainty in the wind fields at the exact time of the measurements. These values are in good agreement with available datasets and with simulated plumes.

Rivera, C.; Sosa, G.; Wöhrnschimmel, H.; de Foy, B.; Johansson, M.; Galle, B.

2009-02-01

49

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

50

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

51

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

52

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

53

Case studies on summertime measurements of O3, NO2, and SO2 with a DOAS system in an urban semi-industrial region in Athens, Greece.  

PubMed

The objective of this study is to analyze the concentrations of SO2, NO2, and O3 measured by a Differential Optical Absorption Spectroscopy (DOAS) system that was operating at the campus of Technological Education Institute of Piraeus during 2008 and 2009 warm periods (July to September) in relation to the prevailing meteorological conditions. The DOAS system was operating in a particularly polluted area of the West part of Attica basin on a continuous basis, measuring the concentration levels of the main pollutants (O3, NO2, and SO2) as well as aromatic hydrocarbon substances (benzene, toluene, and xylene). According to the analysis, the SO2 concentration levels at this measuring site are rather high and this may be attributed to the characteristics of this measuring site. Proximity of roadways and local circulation are just some of the factors that can affect the concentration levels of monitoring of pollutant concentrations such as NO2 and surface ozone. The results provide evidence for the occurrence of an atmospheric phenomenon that produces higher ozone concentrations during weekends despite lower concentrations of ozone precursors. This phenomenon is known as the weekend effect. PMID:23430070

Psiloglou, Betaasil E; Larissi, Ioanna K; Petrakis, Muichael; Paliatsos, Athanasios G; Antoniou, Alphantonis; Viras, Loisos G

2013-09-01

54

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

55

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

NASA Astrophysics Data System (ADS)

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

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

2007-05-01

56

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

57

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

58

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

59

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...

60

[Research on in-situ monitoring of SO2 concentration in the flue gases with DOAS method based on algorithm fusion].  

PubMed

Valuable achievements on differential optical absorption spectroscopy (DOAS) for monitoring atmospheric pollutants gas have been made in the past decades. Based on the idea of setting the threshold according to the maximum value, symbolized as OD'm, of differential optical density, the algorithm of traditional DOAS was combined with the DOAS algorithm based on the kalman filtering to improve the detection limit without losing measurement accuracy in the present article. Two algorithms have different inversion accuracy at the same ratio of signal to noise and the problem of inversion accuracy was well resolved by combining two algorithms at short light path length. Theoretical and experimental research on the concentration measurement of SO2 in the flue gases was carried out at the normal temperature and atmospheric pressure. The research results show that with the OD'm less than 0.0481, the measurement precision is very high for SO2 with the improved DOAS algorithm. The measurement lower limit of SO2 is less than 28.6 mg x m(-3) and the zero drift of the system is less than 2.9 mg x m(-3). If the OD'm is between 0.0481 and 0.9272, the measurement precision is high with the traditional DOAS algorithm. However, if the OD'm is more than 0.922, the errors of measurement results for both two DOAS algorithms are very large and the linearity correction must be performed. PMID:19626898

Tang, Guang-hua; Xu, Chuan-long; Shao, Li-tang; Yang, Dao-ye; Zhou, Bin; Wang, Shi-min

2009-04-01

61

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

NASA Technical Reports Server (NTRS)

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

Jellinek, H. H. G.

1972-01-01

62

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

PubMed Central

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

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

2010-01-01

63

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

64

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

65

SO2 Measurements with Sciamachy  

Microsoft Academic Search

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

Andreas Richter; Folkard Wittrock; J. P. Burrows

2006-01-01

66

Reversible inhibition of the pollen germination and the stigma penetration in Crocus vernus ssp. vernus (Iridaceae) following fumigations with NO2, CO, and O3 Gases.  

PubMed

We assessed the pollen hydration, the pollen germination, and the stigma papilla penetration of CROCUS VERNUS subsp. VERNUS (Iridaceae) after 2 h fumigations with O (3), NO (2), and CO gases within humidified (90 - 100 % RH) box experiments. When the pollen and the pistil were separately fumigated, the pollen retained the capacity to emit a tube which penetrated papilla, and the stigma papillae retained the receptivity; when the pistils were first pollinated and then fumigated, the capacity of pollen to hydrate was not affected, but the germination was significantly reduced. The vulnerability to gases became evident at 0.3 ppm O (3), 0.2 ppm NO (2), and 0.5 ppm CO. The inhibition curves as a function of the gas concentrations were of an exponential type, and they saturated at 2 ppm NO (2), 25 ppm CO, and 0.5 ppm O (3), with germination percentages of 17 %, 27 %, and 60 %, respectively. Both the pollen germination and the papilla penetration were fully restored by prolonging for 60 - 90 min the incubation at 90 - 100 % RH, after the cessation of fumigations. The vulnerability of the pollen-papilla system is discussed. PMID:17564951

Chichiriccò, G; Picozzi, P

2007-11-01

67

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

68

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

69

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

70

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

71

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

72

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

73

SO2 on Io: A thermodynamic perspective  

NASA Technical Reports Server (NTRS)

The presence of condensed SO2 on Io mandates a finite abundance of SO2 vapor which must be present, regardless of plume activity. The absorption of SO2 was measured on particulate sulfur and the equilibrium between absorbed SO2, SO2 vapor, and SO2 ice examined, based upon measurements and simple thermodynamic considerations.

Zent, Aaron P.; Fanale, Fraser P.

1987-01-01

74

Monitoring of volcanic emissions of SO2 and ash  

NASA Astrophysics Data System (ADS)

Volcanic eruptions can emit large quantities of fine particles (ash) into the atmosphere as well as several trace gases, such as water vapour, carbon dioxide, sulphur species (SO2, H2S) and halogens (HCl, HBr, HF). These volcanic ejecta can have a considerable impact on the atmosphere, human health and society. Volcanic ash in particular is known to be a major threat for aviation, especially after dispersion over long distances (>1000 km) from the erupting volcano. In this respect, the continuous monitoring of volcanic ash from space is playing an essential role for the mitigation of aviation hazards. Compared to ash, SO2 is less critical for aviation safety, but is much easier to measure. Therefore, SO2 observations are often use as a marker of volcanic ash in the atmosphere. Moreover, SO2 yields information on the processes occurring in the magmatic system and is used as a proxy for the eruptive rate. In this presentation we give an overview of recent developments of the Support to Aviation Control Service (SACS). The focus is on the near-real time detection and monitoring of volcanic plumes of ash and SO2 using polar-orbiting instruments GOME-2, OMI, IASI and AIRS. The second part of the talk is dedicated to the determination of volcanic SO2 fluxes from satellite measurements. We review different techniques and investigate the temporal evolution of the total emissions of SO2 for recent volcanic events.

Theys, Nicolas; Clarisse, Lieven; Brenot, Hugues; van Gent, Jeroen; Campion, Robin; van der A, Ronald; Valks, Pieter; Corradini, Stefano; Merucci, Luca; Van Roozendael, Michel; Coheur, Pierre-François; Hurtmans, Daniel; Clerbaux, Cathy; Tait, Steve; Ferrucci, Fabrizio

2013-04-01

75

STATUS OF SO2 SCRUBBING TECHNOLOGIES  

EPA Science Inventory

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

76

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

77

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

78

New developments to improve SO2 cameras  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

79

SO2 removal with ferric sulfate solution.  

PubMed

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

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

2008-04-01

80

5, 20172045, 2005 AMAXDOAS SO2  

E-print Network

are combustion of fossil fuels, for example in electric power plants, refinery emissions, and to a lesser degree- formed spectroscopic measurements of SO2 from the city of Mantova and the power plant Porto Tolle using

Paris-Sud XI, Université de

81

Interspecific Variation in SO2 Flux 1  

PubMed Central

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

Olszyk, David M.; Tingey, David T.

1985-01-01

82

CO2-SO2 clathrate hydrate formation on early Mars  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

83

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...

84

Long life Li/SO2 cells  

NASA Astrophysics Data System (ADS)

The development of a long life Li/SO2 battery (one that could operate continuously for periods of at least five years) is discussed. The causes of premature failures in battery concepts are defined and solutions to these problems are described. In particular the corrosion of the glass in a glass-to-metal seal and a spot welded positive lead are addressed.

Levy, S.

1981-03-01

85

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

Microsoft Academic Search

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

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

2010-01-01

86

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

Microsoft Academic Search

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

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

2007-01-01

87

The Weidenbrunnen spruce forest (Fichtelgebirge, Germany): Vertical concentration and flux profiles of non-reactive (CO2, H2O) and reactive (NO, NO2, O3) trace gases  

NASA Astrophysics Data System (ADS)

From 05th of June to 11th of July 2008, the second Intensive Observation Period (IOP-2) of the EGER project (ExchanGE processes in mountainous Regions) was conducted at the spruce forest site "Weidenbrunnen" (Fichtelgebirge/ Germany). The project is focused on the role of process interactions among the different scales of soil, in-canopy and atmospheric exchange processes of reactive and non-reactive trace gases and energy. Within that framework, tower-based vertical profiles of both reactive (NO, NO2, O3) and non-reactive (CO2, H2O) trace gas mixing ratios were measured in and above the spruce forest canopy (mean canopy height: 23 m). Measurements were performed continuously by two identical but independently operating analyzing units, one for in-canopy (at 0.005, 0.03, 0.1, 0.3, 0.9, 3, 10 and 16.5 m above ground) and the other for above-canopy intake levels (at 16.5, 20.5, 25, and 31.5). Accompanying measurements comprise vertical profiles of wind speed, air temperature, momentum, sensible and latent heat, global and photosynthetic active radiation, as well as the NO2 photolysis rate. During IOP-2, we observed NO mixing ratios between 0.2 ppb and 5.1 ppb at the forest floor (0.005 m) not showing a diurnal trend. Above the canopy (31.5 m) NO mixing ratios ranged between 3.4 ppb (day) and ~0.01 (night). At forest floor and above canopy, the NO2 mixing ratios were between 0.3 ppb - 9.2 and 0.7 ppb - 15.5 ppb, respectively. O3 mixing ratios varied at the forest floor between 56.9 ppb (day) and 5.8 ppb (night) and above the canopy 79.3 ppb (day) and 22.4 ppb (night). In our contribution we will focus on (a) detailed quality assessment of the concentration data (temperature dependency of analysers, side-by-side measurements with other systems, response tests, accuracy and detection limits), (b) evaluation of time scales of turbulent mixing and chemical reactions (to elucidate whether or not chemical transformations of the NO-O3-NO2 triad had a noticeable effect on their vertical flux divergence), (c) determination of vertical profiles of CO2, H2O, NO, NO2, and O3 by application of a new numerical flux-gradient algorithm (considering NO-O3-NO2 transformations).

Plake, D.; Moravek, A.; Tsokankunku, A.; Breuninger, C.; Welling, M.; Andreae, M. O.; Meixner, F. X.

2009-04-01

88

40 CFR 96.288 - CAIR SO 2 allowance allocations to CAIR SO 2 opt-in units.  

Code of Federal Regulations, 2013 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2013-07-01

89

40 CFR 97.288 - CAIR SO 2 allowance allocations to CAIR SO 2 opt-in units.  

Code of Federal Regulations, 2013 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2013-07-01

90

40 CFR 96.288 - CAIR SO 2 allowance allocations to CAIR SO 2 opt-in units.  

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2014-07-01

91

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

Code of Federal Regulations, 2011 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2011-07-01

92

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

Code of Federal Regulations, 2010 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2010-07-01

93

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

Code of Federal Regulations, 2012 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2012-07-01

94

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

Code of Federal Regulations, 2012 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2012-07-01

95

40 CFR 97.288 - CAIR SO 2 allowance allocations to CAIR SO 2 opt-in units.  

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2014-07-01

96

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

Code of Federal Regulations, 2011 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2011-07-01

97

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

Code of Federal Regulations, 2010 CFR

...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu) determined...CAIR SO2 opt-in unit's baseline SO2 emissions rate (in lb/mmBtu)...

2010-07-01

98

SO2:HCl ratios in the plumes from Mt. Etna and Vulcano determined by Fourier transform spectroscopy  

Microsoft Academic Search

Volcanic gases have important climate and environmental effects, and provide insights into magmatic processes. Direct sampling of volcanic gases is inherently difficult and often hazardous. Here, we report the results of long path measurements of SO2 and HCl from Mt. Etna and Vulcano (Italy) obtained by active mode Fourier Transform Infrared (FTIR) spectroscopy. Spectra recorded in September 1994 over paths

Peter Francis; Adam Maciejewski; Clive Oppenheimer; Charles Chaffin; Tommaso Caltabiano

1995-01-01

99

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

100

Volcanic SO2 Flux Derived From Satellite And From NOVAC Ground-based Systems  

NASA Astrophysics Data System (ADS)

The main objective of the NOVAC project (Network for Observation of Volcanic and Atmospheric Change) is to establish a global network of stations for the quantitative measurement of volcanic SO2 emissions by UV absorption spectroscopy. The data from the network (more than 21 volcanoes are currently monitored) are primarily used for risk assessment and volcanological research, but the data are also valuable for the study of tropospheric and stratospheric gas composition (SO2, NO2, CH2O, BrO and O3). Since volcanic SO2 is also monitored from satellite (e.g. the SACS service, http://sacs.aeronomie.be/) the NOVAC project provides an excellent opportunity to explore and inter-compare the different satellite SO2 data-sets under volcanic conditions. Furthermore the NOVAC ground-based data can then be used to validate satellites estimates of gas flux emissions. In this work, we present an investigation focusing on GOME-2 and OMI SO2 data sets. Their mutual consistency is analysed and comparisons of SO2 flux estimates are performed using NOVAC ground-based network measurements. A case study over Etna involving OMI (Ozone Monitoring Instrument) and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is presented that illustrates the impact of spatial inhomogeneities in the SO2 field inside the area covered by an OMI pixel. This study illustrates the importance of external information (as the height of the volcanic plume) to reduce the error on the SO2 estimation.

Pinardi, Gaia; van Roozendael, Michel; Fayt, Caroline; van Geffen, Jos; Campion, Robin; Galle, Bo; Carn, Simon; Valks, Pieter; Rix, Meike

2010-05-01

101

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...

102

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

E-print Network

) and a catalyst. The second reaction, the SO2-depolarized electrolysis of water, * Corresponding author. Tel.: �1 is the split- ting of one mole of water into one mole of hydrogen and one half mole of oxygen. This paperA thermodynamic analysis of the SO2/H2SO4 system in SO2-depolarized electrolysis Maximilian B

Weidner, John W.

103

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

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

104

Model Simulations of the Competing Climatic Effects of SO2 and CO2  

Microsoft Academic Search

Sulfur dioxide-derived cloud condensation nuclei are expected to enhance the planetary albedo, thereby cooling the planet. This effect might counteract the global warming expected from enhanced greenhouse gases. A detailed treatment of the relationship between fossil fuel burning and the SO2 effect on cloud albedo is implemented in a two-dimensional model for assessing the climate impact. Although there are large

Yoram J. Kaufman; Ming-Dah Chou

1993-01-01

105

SO 2 adsorption and desorption kinetics on Pt(111)  

NASA Astrophysics Data System (ADS)

SO 2/Pt(111) adsorption and desorption kinetics in the temperature range 160-300 K were investigated by molecular beam technique and TDMS measurements. The initial sticking probability s0SO2 turns out to be unity independent of surface temperature, and the SSO 2(?) curves indicate the operation of a precursor mechanism. The TDMS spectra of SO 2 could be analysed by means of second order desorption kinetics indicating that SO 2 seems to be adsorbed dissociatively even at low temperatures (at least for small coverages). The resulting kinetic parameters are interpreted as values determining the recombination process (SO) ad + O ad ? (SO 2) ad, assuming the SO 2 molecule to desorb directly. Combining these results with those on SO dissociation and recombination recently obtained by us, it was possible to complete our proposed potential energy diagram for sulfur-oxygen reactions on Pt(111).

Köhler, U.; Wassmuth, H.-W.

1983-03-01

106

How to select filter fabrics for dry SO2 systems  

SciTech Connect

The baghouse fabric does not have much of an effect on SO2 removal efficiency since the efficiency depends primarily on the type and amount of sorbent used, the residence time, and other factors. Most dry-scrubbing processes provide SO2 removal frequencies of above 70-80%. The choice and characteristics of baghouse fabrics, including woven fabric, needled felts, homopolymer acrylic, and fiberglass, and baghouse functions associated with SO2 removal are discussed.

Bergmann, L.

1980-09-01

107

Effects of prolonged exposure of Oryzopsis hymenoides to SO 2  

Microsoft Academic Search

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

Roger W. Ferenbaugh

1978-01-01

108

SO2 and CO2 removal from flue gas  

Microsoft Academic Search

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

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

2006-01-01

109

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

110

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

NASA Astrophysics Data System (ADS)

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

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

111

Evaluation of ambient SO 2 measurement methods at roadside sites  

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

112

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

NASA Astrophysics Data System (ADS)

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

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

1994-08-01

113

SO2 flux measurements at Mount Etna (Sicily)  

Microsoft Academic Search

Since 1987, over 220 measurements of the SO2 flux at Mount Etna have been carried out using a correlation spectrometer (COSPEC) with different measuring techniques (mainly with COSPEC mounted on ground-based vehicle). This paper reports and analyzes the data obtained between October 1987 and December 1991. During this period, three distinct time intervals characterized by particular SO2 emission patterns were

Tommaso Caltabiano; Romolo Romano; Gennaro Budetta

1994-01-01

114

Reversible capture of SO2 through functionalized ionic liquids.  

PubMed

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

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

2013-07-01

115

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 ...

116

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...

117

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...

118

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

119

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

120

Performance of the HPLC/fluorescence SO2 detector during the GASIE instrument intercomparison experiment  

NASA Astrophysics Data System (ADS)

Sulfur dioxide (SO2) in synthetic air and diluted ambient air was measured as part of the Gas-Phase Sulfur Intercomparison Experiment (GASIE) using the high performance liquid chromatography (HPLC)/fluorescence technique. SO2 was analyzed by equilibrating the gaseous sample with aqueous SO2, sulfite, and bisulfite, then converting the aqueous S(IV) to an isoindole derivative. The derivative was separated by reversed phase HPLC and detected via fluorescence. The system was calibrated with mixtures of SO2 in zero air prepared from an SO2 permeation device through a two-stage dilution system. The instrument has a 4-min. sample integration time and a measurement period of 9-min. During the GASIE intercomparison the lower limit of detection averaged 3.6 parts per trillion by volume (pptv). The precision of replicate measurements over the entire intercomparison period was better than 5% at the 20 pptv level. Instrument performance was unaffected by the interferent gases included in the GASIE protocol (H2O, O3, NOx, DMS, CO, CO2, and CH4). During diluted ambient air tests, the HPLC/fluorescence technique exhibited an approximately 10% reduction in response relative to some other techniques. The cause of this apparent calibration change is not understood.

Gallagher, M. S.; King, D. B.; Whung, P.-Y.; Saltzman, E. S.

1997-07-01

121

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

Microsoft Academic Search

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

Klaus Schäfer; Rainer Haus; Jörg Heland

1994-01-01

122

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

PubMed

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

Feng, Wenguo; Jia, Charles Q

2005-12-15

123

Surface Hydrophobicity Causes SO2 Tolerance in Lichens  

PubMed Central

Background and Aims The superhydrophobicity of the thallus surface in one of the most SO2-tolerant lichen species, Lecanora conizaeoides, suggests that surface hydrophobicity could be a general feature of lichen symbioses controlling their tolerance to SO2. The study described here tests this hypothesis. Methods Water droplets of the size of a raindrop were placed on the surface of air-dry thalli in 50 lichen species of known SO2 tolerance and contact angles were measured to quantify hydrophobicity. Key Results The wettability of lichen thalli ranges from strongly hydrophobic to strongly hydrophilic. SO2 tolerance of the studied lichen species increased with increasing hydrophobicity of the thallus surface. Extraction of extracellular lichen secondary metabolites with acetone reduced, but did not abolish the hydrophobicity of lichen thalli. Conclusions Surface hydrophobicity is the main factor controlling SO2 tolerance in lichens. It presumably originally evolved as an adaptation to wet habitats preventing the depression of net photosynthesis due to supersaturation of the thallus with water. Hydrophilicity of lichen thalli is an adaptation to dry or humid, but not directly rain-exposed habitats. The crucial role of surface hydrophobicity in SO2 also explains why many markedly SO2-tolerant species are additionally tolerant to other (chemically unrelated) toxic substances including heavy metals. PMID:18077467

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

2008-01-01

124

Supported polytertiary amines: highly efficient and selective SO2 adsorbents.  

PubMed

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

Tailor, Ritesh; Abboud, Mohamed; Sayari, Abdelhamid

2014-02-01

125

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

126

Mesophyll Resistances to SO2 Fluxes into Leaves 1  

PubMed Central

Uptake of label from solutions containing 35SO2, H35SO3? and 35SO32? into mesophyll protoplasts, vacuoles, and chloroplasts isolated from young barley leaves was measured at different pH values. Uptake was fast at low pH, when the concentration of SO2 was high, and low at high pH, when the concentration of SO2 was low. When the resistance (R) of plasmalemma, tonoplast, and chloroplast envelope to the penetration of SO2 was calculated from rates of uptake of label, comparable values were obtained for the different biomembranes at low pH values. R was close to 8000 seconds per meter and permeability coefficients were close to 1.25 × 10?4 meters per second. Under these conditions R may describe resistance to SO2 diffusion across a lipid bilayer. At higher pH values, R decreased. As R was calculated on the assumption that SO2 is the only penetrating molecular species, the data suggest that carrier-mediated anion transport contributes to the uptake of sulfur at physiological pH values thereby decreasing apparent RSO2. The contribution of anion transport appeared to be smaller for transfer across the plasmalemma than for transfer across the tonoplast. It was large for transfer across the chloroplast envelope. The phosphate translocator of the chloroplast envelope catalyzed uptake of SO32? into chloroplasts at neutral pH. Uptake was decreased in the presence of high levels of phosphate or sulfate and by pyridoxal phosphate. SO2 transfer into cells leads to the intracellular liberation of one or two protons, depending on pH and oxidizing conditions. When the divalent sulfite anion is exchanged across the chloroplast envelope, bisulfite formation results in proton uptake in the chloroplast stroma, whereas SO2 uptake into chloroplasts lowers the stroma pH. PMID:16665832

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

1987-01-01

127

Fluctuations in SO2 emission during recent eruptions of Etna  

Microsoft Academic Search

THE eruptive activity of July-August 1977 of Mt Etna consisted of four separate, short eruptive episodes: 16-22 July; 5-6 August; 14 August; 24 August. The rate of SO2 emission during these eruptions was monitored using a remote-sensing correlation spectrometer. These data suggest that fluctuations in the SO2 emission rate provide a means for predicting eruptions of Etna.

Lawrence L. Malinconico

1979-01-01

128

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

129

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

130

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

131

Efficient low-temperature oxidation of carbon-cluster anions by SO2.  

PubMed

Carbon-cluster anions, CN-, are very reactive toward SO2 (sticking probability of 0.012 +/- 0.005 for C27- at 25 degrees C), in contrast to their inertness toward other common atmospheric gases and pollutants. In flow reactor experiments at ambient temperature and near atmospheric pressure, primary adsorption of SO2 by the carbon cluster anions, N = 4-60, yields CNSO2- or CN-1S-. The inferred elimination of neutral CO2 is also detected as meta-stable decay in collision-induced dissociation. At higher temperatures, the reaction of SO2 with nascent carbon clusters yields CN-1SO- as well as undetected CO. The size-dependent initial reactivity reflects the previously established structural transitions (i.e., from chain to cyclic to cage structures). Such carbon clusters are formed in sooting flames and may act as nuclei for the formation of primary soot particles and serve as models for the local structural features of active soot particle sites for black-carbon soot. The facile generation of reactive carbon-sulfide and -sulfinate units may therefore have implications for understanding the health and environmental effects attributed to the coincidence of soot and SO2. PMID:16833961

Leavitt, Andrew J; Wyrwas, Richard B; Wallace, William T; Serrano, Daniel S; Arredondo, Melissa G; Leslie, Logan M; Khan, Farooq A; Whetten, Robert L

2005-07-21

132

Model simulations of the competing climatic effects of SO2 and CO2  

NASA Technical Reports Server (NTRS)

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

Kaufman, Yoram J.; Chou, Ming-Dah

1993-01-01

133

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

134

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

135

BrO/SO2 ratios from the NOVAC network  

NASA Astrophysics Data System (ADS)

The halogen/sulphur ratio is an important indicator for dynamical changes in the upper part of a volcanic system. In particular, the BrO/SO2 ratio was recently suggested to be an indicator for changes in volcanic activity. This ratio can be assessed by Differential Optical Absorption Spectroscopy measurements in the UV. SO2 is emitted by volcanoes and relatively stable on time-scales usually observed during ground-based remote-sensing measurements. On the other hand, BrO is not directly released from volcanoes, but probably a product of photochemical oxidation of primary emitted HBr in the atmosphere. This study presents BrO/SO2 ratios measured from the Network for Observation of Volcanic and Atmospheric Change (NOVAC). NOVAC has so far installed 64 spectrometers at 24 volcanoes world-wide, some of which measure volcanic gas and their fluxes for 7 years. This vast database will allow to correlate changes in the BrO/SO2 ratio with volcanic activity and to investigate other parameters that might influence the formation of BrO in the volcanic plume, i.e., meteorology and time since release from the volcano. We show that it is possible to obtain BrO/SO2 ratios from the Type 1 NOVAC instrumentation at Nevado del Ruiz, Colombia, and present an adapted data evaluation scheme. Issues in the evaluation of automatically acquired spectroscopic data will be discussed and possible solutions will be suggested and application to the data will be shown. This includes the correct parameter settings for the BrO and SO2 evaluation, the availability of reference spectra and problems with the variation of the instrument temperature. Measurement results and BrO/SO2 time-series will be presented and the possibilities of the data set will be illustrated.

Lübcke, Peter; Bobrowski, Nicole; Galle, Bo; Garzon, Guastavo; Vogel, Leif; Platt, Ulrich

2013-04-01

136

Deposition of particulate matter in diffusion tube samplers for the determination of NO 2 and SO 2  

NASA Astrophysics Data System (ADS)

The applicability of tube-like diffusion samplers for the determination of ambient air concentrations of sulfur dioxide and nitrogen dioxide was evaluated. The diffusion tubes were made from polyethylene and triethanolamine was used as an absorbent. Artifacts due to the deposition of gaseous or particulate compounds to the tube walls were considered. With respect to sampling of nitrogen dioxide no interference by the tube walls could be observed. The determination of sulfur dioxide was strongly biased by the collection of particulate sulfate at the entrance part of the tube and along the tube walls. This effect leads to a large overestimation of the average air concentrations compared with fluorescence monitors.

Kasper-Giebl, A.; Puxbaum, H.

137

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

138

Signature current of SO2-induced bronchitis in rabbit.  

PubMed Central

To investigate abnormalities of airway epithelial ion transport underlying chronic inflammatory airway diseases, we performed electrophysiological, histological, and molecular biological experiments using rabbits exposed to SO2 as a model of bronchitis. By comparison with control, the SO2-exposed trachea exhibited decreased short circuit current (Isc) and conductance associated with increased potential difference. In normal trachea, apical ATP induced a transient Isc activation followed by a suppression, whereas the bronchitis model exhibited a prolonged activation without suppression. This pathological ATP response was abolished by diphenylamine 2-carboxylate or Cl--free bath solution. A significant increase in net Cl- flux toward the lumen was observed after ATP in our bronchitis model. Isoproterenol or adenosine evoked a sustained Isc increase in SO2-exposed, but not in normal, tracheas. The Northern blot analysis showed a strong expression of cystic fibrosis transmembrane conductance regulator (CFTR) mRNA in SO2-exposed epithelium. The immunohistochemical study revealed a positive label of CFTR on cells located luminally only in SO2-exposed rabbits. We concluded that the prolonged ATP response in our bronchitis model was of a superimposed normal and adenosine-activated current. The latter current was also activated by isoproterenol and appeared as a signature current for the bronchitis model airway. This was likely mediated by CFTR expressed in the course of chronic inflammation. PMID:9120009

Iwase, N; Sasaki, T; Shimura, S; Fushimi, T; Okayama, H; Hoshi, H; Irokawa, T; Sasamori, K; Takahashi, K; Shirato, K

1997-01-01

139

SO2 noontime peak phenomenon in the North China Plain  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

140

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

141

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

142

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

NASA Astrophysics Data System (ADS)

Sulfur dioxide-derived cloud condensation nuclei are expected to enhance the planetary albedo, thereby cooling the planet. This effect might counteract the global warming expected from enhanced greenhouse gases. A detailed treatment of the relationship between fossil fuel burning and the SO2 effect on cloud albedo is implemented in a two-dimensional model for assessing the climate impact. Although there are large gaps in our knowledge of the atmospheric sources and sinks of sulfate aerosol, it is possible to reach some general conclusions. Using a conservative approach, results show that the cooling induced by the SO2 emission can presently counteract 50% of the CO2 greenhouse warming. Since 1980, a strong warming trend has been predicted by the model, 0.15°C, during the 1980-1990 period alone. The model predicts that by the year 2060 the SO2 cooling reduces climate warming by 0.5°C or 25% for the Intergovernmental Panel on Climate Change (IPCC) business as usual (BAU) scenario and 0.2°C or 20% for scenario D (for a slow pace of fossil fuel burning). The hypothesis is examined that the different responses between the Northern Hemisphere (NH) and the Southern Hemisphere (SH) can be used to validate the presence of the SO2-induced cooling. Despite the fact that most of the SO2-induced cooling takes place in the Northern Hemispheric continents, the model-predicted difference in the temperature response between the NH and the SH of 0.2°C in 1980 is expected to remain about the same at least until 2060. This result is a combined effect of the much faster response of the continents than the oceans and of the larger forcing due to CO2 than due to the SO2. The climatic response to a complete filtering of SO2 from the emission products in order to reduce acid rain is also examined. The result is a warming surge of 0.4°C in the first few years after the elimination of the SO2 emission.

Kaufman, Yoram J.; Chou, Ming-Dah

1993-07-01

143

DEVELOPMENT OF AN SO2 MONITOR FOR MOBILE SOURCES  

EPA Science Inventory

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

144

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...

145

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 ...

146

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...

147

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...

148

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/...

149

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...

150

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

151

INTRASPECIFIC VARIABILITY IN METABOLIC RESPONSES TO SO2  

EPA Science Inventory

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

152

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...

153

Safety characteristics of the lithium SO2 system  

NASA Technical Reports Server (NTRS)

Extensive tests were conducted to quantitatively define the safety characteristics of high-rate SO2 multicell batteries under various discharge and temperature profiles, which closely simulated actual field-use conditions. The resulting behavior patters of the multicell batteries and the corrective action which can be implemented to minimize or prevent hazardous battery performance are briefly summarized.

Watson, T.

1978-01-01

154

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...

155

Photochemical reaction dynamics in SO2-acetylene complexes  

NASA Astrophysics Data System (ADS)

The dynamics of photoinduced reactions between electronically excited SO2 molecule (A~ 1A2<--X~ 1A1) and acetylene molecule (X~ 1?g+) in the SO2-acetylene van der Waals (vdW) complexes (clusters) was studied. The SO2 molecule was excited by frequency-doubled radiation of a tunable dye laser, and resonance enhancement multiphoton photoionization of the produced photofragments was induced by ArF (193 nm) laser radiation or by frequency-doubled radiation of a second tunable dye laser to observe the C2H radical. The HOSO radical was detected by its IR emission. We found that the main photodecomposition channel of the vdW complexes (clusters) involves the SO2*+C2H2-->HOSO+C2H reaction. Indeed, the analysis of the action spectra of the excitation laser radiation showed that the photofragments emerging in our experimental conditions (SO2, 5% C2H2, 5% and Xe; P0=2 atm) originate from the SO2...C2H2 vdW complex (cluster). We analyzed the structure of this vdW complex theoretically, obtaining Cs symmetry, with the acetylene molecule located above the OSO plane. The resonance-enhanced multiphoton photoionization action spectra of the C2H (A~<--X~) photofragmentation and the IR emission spectra of the HOSO radical allowed the authors to probe the energy distribution between the photofragments formed. The reaction that involves transition of the acetylene H atom to the SO2 oxygen should be the primary step of the process considered, followed by nonstatistic dissociation of the vdW complex (cluster), with the C2H radical formed in its vibrationless state and excited both rotationally and translationally, and the HOSO radical excited vibrationally, rotationally and translationally. The proposed reaction mechanism was discussed, employing transition-state and Rice-Ramsperger-Kassel-Marcus (RRKM) approaches. The kinetics of photofragment formation was investigated, yielding characteristic radical build-up time of 0.64 ?s.

Makarov, Vladimir I.; Kochubei, Sergei A.; Khmelinskii, Igor

2010-06-01

156

Simultaneous absorption of SO2 and NO from flue gas with KMnO4/NaOH solutions.  

PubMed

The wet scrubbing combined SOx/NOx removal system is an advanced air pollution control device. This study attempts to understand the absorption kinetics in the system. The absorption of diluted SO2 and simultaneous absorption of diluted SO2 and NO, as occurs in flue gases, in a stirred tank reactor with KMnO4/NaOH solutions were carried out at 50 degrees C. The liquid-side and gas-side mass transfer coefficients of the system were determined. The results indicate that the absorption of SO2 is close to completely gas-film controlled where the NaOH concentration is greater than 0.1 M or the KMnO4 concentration is greater than 0.05 M. The increasing gas flow rate has a positive effect on the absorption rate of SO2. The existence of O2 has no significant effect on the absorption rate of SO2. Adding SO2 would decrease the absorption rate of NO; however, the addition of NO has no effect on the absorption rate of SO2. PMID:11482398

Chu, H; Chien, T W; Li, S Y

2001-07-25

157

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

NASA Astrophysics Data System (ADS)

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

Osiensky, J.; Hall, T.

2008-12-01

158

Cost-effective control of SO 2 emissions in Asia  

Microsoft Academic Search

Despite recent efforts to limit the growth of SO2 emissions in Asia, the negative environmental effects of sulphur emissions are likely to further increase in the future. This paper presents an extension of the RAINS-Asia integrated assessment model for acidification in Asia with an optimisation routine that can be used to identify cost-effective emission control strategies that achieve environmental targets

J. Cofala; M. Amann; F. Gyarfas; W Schoepp; J. C. Boudri; L. Hordijk; C. Kroeze; Li Junfeng; D. Dai Lin; T. S. Panwar; S. Gupta

2004-01-01

159

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

160

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

E-print Network

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

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

2014-09-05

161

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

E-print Network

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

Sadeghian, S; Yavartanoo, H

2014-01-01

162

Sputtering of SO2 by high energy ions  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

163

Monitoring of SO2 emissions from industry by passive DOAS  

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

164

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

165

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

NASA Astrophysics Data System (ADS)

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

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

166

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

PubMed

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

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

2013-11-01

167

Laser stark spectroscopy of SO2 with the HCN laser  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

168

SO2 Emission Control: The Problem and Solutions  

NASA Astrophysics Data System (ADS)

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

Friedman, Leonard J.

1981-03-01

169

The ground state rotational spectrum of SO 2F 2  

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

170

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

Microsoft Academic Search

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

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

1989-01-01

171

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

PubMed Central

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

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

2011-01-01

172

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

173

Io's Thermal Regions and Non-SO2 Spectral Features  

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

174

Measurement of SO2 effects on the 218Po ion mobility spectrum by alpha-track detection.  

PubMed

A number of investigators have reported the formation of radiolytic ultrafine particles produced by the interaction of ionizing radiation with atmospheric trace gases. Previous studies have suggested that a very high localized concentration of the OH radical produced by the radiolysis of water can react with atmospheric trace gas, like SO2, to produce lower vapor pressure compounds that can then nucleate. To determine trace-gas dependence of the active, positively charged, first decay product of radon, the mobility spectrum of the decay products in the range of 0.06-3.0 cm2 V-1s-1 was measured in a flow-through radon chamber using a specially designed mobility spectrometer. Measurements were taken for different relative humidities and concentrations of SO2 in purified laboratory compressed air. The resultant mobility spectra were compared with radiolytic ultrafine particle activity distribution data. In the case of low humidities, the reduction of available OH concentration and hence neutralization rate led to the increasing intensity of the shoulder around 1.35 cm2 V-1s-1 with increasing SO2, suggesting SO2 clustering around the PoOx+ ion. For high humidity conditions (5 ppm SO2, 30% RH), there was clear droplet formation, H2SO4, clustering around the ion, and also an increase in the background level between the high mobility peak and droplet peak. PMID:1309229

Yoon, S C; Marlow, W H; Hopke, P K

1992-01-01

175

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

E-print Network

Spatially extended systems, such as Navier-Stokes equations, 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 symmetry action, such as a translation or a rotation. `Symmetry reduction' is a coordinate transformation which separates the state space into a lower-dimensional, symmetry-reduced state space, where every set of symmetry-equivalent states is represented by a single state, and `phase' coordinates which enable one to reconstruct the original, full state space dynamics. In the method of slices this reduction is achieved locally by cutting all group orbits by a `slice'. Here we describe the `first Fourier mode slice', a simple application of the method to reduction of SO(2) symmetry, in which singularities in phase velocity close to the slice border are regularized by a time-scaling transformation. We show that global structures, such as chaotic attractors and unstable manifolds of traveling waves, are uncovered in the symmetry-reduced state space. We illustrate the method by applying it to a two-Fourier modes normal-form model and to the Kuramoto-Sivashinsky system.

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

2014-05-05

176

Modeling of SO(2) scrubbing in spray towers.  

PubMed

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

Bandyopadhyay, Amitava; Biswas, Manindra N

2007-09-20

177

Mass transfer in the absorption of SO2 and NO(x) using aqueous euchlorine scrubbing solution.  

PubMed

Attempts have been made to generate euchlorine gas by chlorate-chloride process and to utilize it further to clean up SO2 and NO(x) from the flue gas in a lab scale bubbling reactor. Preliminary experiments were carried out to determine the gas and liquid phase mass transfer coefficients and their correlation equations have been established. Simultaneous removal of SO2 and NO(x) from the simulated flue gas using aqueous euchlorine scrubbing solution has been investigated. Euchlorine oxidized NO into NO2 completely and the later subsequently absorbed into the scrubbing solution in the form of nitrate. SO2 removal efficiency around 100% and NO(x) removal efficiency around 72% were achieved under optimal conditions. Mass balance has been confirmed by analyzing the sulfate, nitrate, euchlorine and chloride ion using ion chromatograph/auto-titrator and comparing it with their corresponding calculated values. PMID:19402415

Deshwal, Bal-Raj; Lee, Hyung-Keun

2009-01-01

178

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

Federal Register 2010, 2011, 2012, 2013

...with maintenance of the 1- hour sulfur dioxide (SO 2 ) national ambient...the Act) that emissions of sulfur dioxide (SO 2 ) from the Portland...the Act) that emissions of sulfur dioxide (SO 2 ) from the...

2011-12-22

179

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

Federal Register 2010, 2011, 2012, 2013

...with maintenance of the 1- hour sulfur dioxide (SO 2 ) national ambient...the Act) that emissions of sulfur dioxide (SO 2 ) from the Portland...the Act) that emissions of sulfur dioxide (SO 2 ) from the...

2011-12-22

180

Global Reactive Gases in the MACC project  

NASA Astrophysics Data System (ADS)

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

Schultz, M. G.

2012-04-01

181

Measurements of HONO, NO, NOy and SO2 in aircraft exhaust plumes at cruise  

NASA Astrophysics Data System (ADS)

Measurements of gaseous nitrogen and sulfur oxide emissions in young aircraft exhaust plumes give insight into chemical oxidation processes inside aircraft engines. Particularly, the OH-induced formation of nitrous acid (HONO) from nitrogen oxide (NO) and sulfuric acid (H2SO4) from sulfur dioxide (SO2) inside the turbine which is highly uncertain, need detailed analysis to address the climate impact of aviation. We report on airborne in situ measurements at cruise altitudes of HONO, NO, NOy, and SO2 in 9 wakes of 8 different types of modern jet airliners, including for the first time also an A380. Measurements of HONO and SO2 were made with an ITCIMS (Ion Trap Chemical Ionization Mass Spectrometer) using a new ion-reaction scheme involving SF5- reagent ions. The measured molar ratios HONO/NO and HONO/NOy with averages of 0.038 ± 0.010 and 0.027 ± 0.005 were found to decrease systematically with increasing NOx emission-index (EI NOx). We calculate an average EI HONO of 0.31 ± 0.12 g NO2 kg-1. Using reliable measurements of HONO and NOy, which are less adhesive than H2SO4 to the inlet walls, we derive the OH-induced conversion fraction of fuel sulfur to sulfuric acid $\\varepsilon$ with an average of 2.2 ± 0.5 %. $\\varepsilon$ also tends to decrease with increasing EI NOx, consistent with earlier model simulations. The lowest HONO/NO, HONO/NOy and $\\varepsilon$ was observed for the largest passenger aircraft A380.

Jurkat, T.; Voigt, C.; Arnold, F.; Schlager, H.; Kleffmann, J.; Aufmhoff, H.; Schäuble, D.; Schaefer, M.; Schumann, U.

2011-05-01

182

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

183

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...

184

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

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

185

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

PubMed

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

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

2011-08-15

186

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

NASA Technical Reports Server (NTRS)

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

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

1977-01-01

187

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 Form: June 14, 2004 The chemical kinetics of the Pt catalyzed oxidation reaction SO2(g) + 1/2O2(g) 798

Lin, Xi

188

Infrared absorption of CH3SO2 detected with time-resolved Fourier-transform spectroscopy  

NASA Astrophysics Data System (ADS)

A step-scan Fourier-transform spectrometer coupled with a 6.4m multipass absorption cell was employed to detect time-resolved infrared absorption spectra of the reaction intermediate CH3SO2 radical, produced upon irradiation of a flowing gaseous mixture of CH3I and SO2 in CO2 at 248nm. Two transient bands with origins at 1280 and 1076cm-1 were observed and are assigned to the SO2-antisymmetric and SO2-symmetric stretching modes of CH3SO2, respectively. Calculations with density-functional theory (B3LYP/aug-cc-pVTZ and B3P86/aug-cc-pVTZ) predicted the geometry, vibrational, and rotational parameters of CH3SO2 and CH3OSO. Based on predicted rotational parameters, the simulated absorption band of the SO2-antisymmetric stretching mode that is dominated by the b-type rotational structure agrees satisfactorily with experimental results. In addition, a band near 1159cm-1 observed at a later period is tentatively attributed to CH3SO2I. The reaction kinetics of CH3+SO2?CH3SO2 and CH3SO2+I ?CH3SO2I based on the rise and decay of absorption bands of CH3SO2 and CH3SO2I agree satisfactorily with previous reports.

Chu, Li-Kang; Lee, Yuan-Pern

2006-06-01

189

Temperature effect on ultraviolet differential absorption cross section of SO2  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

190

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

191

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...

192

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

EPA Science Inventory

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

193

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...

194

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

PubMed

Irradiation with a mercury lamp at 254 nm of a p-H(2) matrix containing CH(3)I and SO(2) at 3.3 K, followed by annealing of the matrix, produced prominent features at 633.8, 917.5, 1071.1 (1072.2), 1272.5 (1273.0, 1273.6), and 1416.0 cm(-1), attributable to ?(11) (C-S stretching), ?(10) (CH(3) wagging), ?(8) (SO(2) symmetric stretching), ?(7) (SO(2) antisymmetric stretching), and ?(4) (CH(2) scissoring) modes of methylsulfonyl radical (CH(3)SO(2)), respectively; lines listed in parentheses are weaker lines likely associated with species in a different matrix environment. Further irradiation at 365 nm diminishes these features and produced SO(2) and CH(3). Additional features at 1150.1 and 1353.1 (1352.7) cm(-1) are tentatively assigned to the SO(2) symmetric and antisymmetric stretching modes of ISO(2). These assignments are based on comparison of observed vibrational wavenumbers and (18)O- and (34)S-isotopic shifts with those predicted with the B3P86 method. Our results agree with the previous report of transient IR absorption bands of gaseous CH(3)SO(2) at 1280 and 1076 cm(-1). These results demonstrate that the cage effect of solid p-H(2) is diminished so that CH(3) radicals, produced via UV photodissociation of CH(3)I in situ, might react with SO(2) to form CH(3)SO(2) during irradiation and upon annealing. Observation of CH(3)SO(2) but not CH(3)OSO is consistent with the theoretical predictions that only the former reactions proceed via a barrierless path. PMID:21456669

Lee, Yu-Fang; Lee, Yuan-Pern

2011-03-28

195

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

Code of Federal Regulations, 2012 CFR

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

2012-07-01

196

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

197

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

198

40 CFR 73.19 - Certain units with declining SO 2 rates.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Certain units with declining SO 2 rates. 73.19 Section 73.19 Protection...Allocations § 73.19 Certain units with declining SO 2 rates. (a) Eligibility. A unit is eligible for allowance...

2013-07-01

199

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...

200

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

201

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

PubMed

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

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

2011-11-24

202

Flux of SO2 into Leaf Cells and Cellular Acidification by SO21  

PubMed Central

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

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

1987-01-01

203

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

Microsoft Academic Search

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

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

2007-01-01

204

Development of an ultra-violet digital camera for volcanic SO 2 imaging  

Microsoft Academic Search

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

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

2007-01-01

205

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

206

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

207

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

PubMed

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

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

2000-05-01

208

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

...procedures for SO2, NOX, and flow rate. 75.33 Section 75...PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS...procedures for SO2 , NOX , and flow rate. (a) Following initial...required SO2 , NOX , and flow rate monitoring...

2014-07-01

209

REACTIVATION OF SOLIDS FROM FURNACE INJECTION OF LIMESTONE FOR SO2 CONTROL  

EPA Science Inventory

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

210

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

211

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

212

SO2 columns over China: Temporal and spatial variations using OMI and GOME-2 observations  

NASA Astrophysics Data System (ADS)

Enhancements of SO2 column amounts due to anthropogenic emission sources over China were shown in this paper by using OMI and GOME-2 observations. The temporal and spatial variations of SO2 columns over China were analyzed for the time period 2005-2010. Beijing and Chongqing showed a high concentration in the SO2 columns, attributable to the use of coal for power generation in China and the characteristic of terrain and meteorology. The reduction of SO2 columns over Beijing and surrounding provinces in 2008 was observed by OMI, which confirms the effectiveness of strict controls on pollutant emissions and motor vehicle traffic before and during 2008 Olympic and Paralympic Games. The SO2 columns over China from GOME-2 (0.2-0.5 DU) were lower than those from OMI (0.6-1 DU), but both showed a decrease in SO2 columns over northern China since 2008 (except an increase in OMI SO2 in 2010).

Huanhuan, Yan; Liangfu, Chen; Lin, Su; Jinhua, Tao; Chao, Yu

2014-03-01

213

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

214

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

215

Improved reversibility in aged porous silicon NO 2 sensors  

Microsoft Academic Search

Porous silicon (PS) conductometric gas sensors can exhibit large sensitivity to gases, due to the large surface versus volume ratio of porous silicon. A possible application is the detection of traces of nitrogen dioxide (NO2), an air pollutant. ?G\\/G signals in excess of 10 in the presence of concentrations as low as 50ppb in dry air can be demonstrated. Unfortunately,

L. Pancheri; C. J. Oton; Z. Gaburro; G. Soncini; L. Pavesib

2004-01-01

216

Production of NO2 from Photolysis of Peroxyacetyl Nitrate  

NASA Technical Reports Server (NTRS)

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

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

1965-01-01

217

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

PubMed

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

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

2014-08-15

218

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

219

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.

220

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

221

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

222

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

PubMed

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

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

2007-09-01

223

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

224

Stable sulfur isotope analysis of SO 2 pollution impact on vegetation  

Microsoft Academic Search

The d34S value of SO2 emitted by natural gas refineries is about +25, which is higher than that for non-industrial sulfur sources in our study areas. Terrestrial mosses absorb SO2 from the atmosphere and have a d34S value which is directly related to the degree of SO2 stress to which they are subjected. The d34S values for conifer needles are

William E. Winner; J. Derek Bewley; H. Roy Krouse; Hugh M. Brown

1978-01-01

225

The relation of H2S release to SO2 fumigation of lichens  

Microsoft Academic Search

Hydrogen sulphide emission in lichens as a response to low concentration SO2 fumigation was investigated. In an open flow-through system several lichen species were fumigated with 36 ppb SO2. Two species were also fumigated with higher concentrations (72, 119, 122 and 198 ppb SO2). Hydrogen sulphide emission was monitored concurrently by cryogenic trapping and analysis with gas chromatography. All tested

CORINNA GRIES; JOANNE G. ROMAGNI; THOMAS H. NASH III; UWE KUHN; JURGEN KESSELMEIER

1997-01-01

226

SO2 Over China Detected With EOS Aura Ozone Monitoring Instrument  

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). Publicly released SO2 pollution data are processed with the Band Residual Difference (BRD) algorithm that uses calibrated residuals at SO2 absorption band centers produced by the NASA operational ozone algorithm (OMTO3). By using optimum wavelengths

N. A. Krotkov; P. Bhartia; K. Yang; S. A. Carn; A. J. Krueger; R. R. Dickerson; J. Hains; C. Li; Z. Li; L. Marufu; J. Stehr; P. F. Levelt

2006-01-01

227

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

Microsoft Academic Search

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

Xiaohua Xu; Hong Jiang; Yueqi Wang; Xiuying Zhang

2010-01-01

228

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

Microsoft Academic Search

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

S. Bekki

1995-01-01

229

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

Microsoft Academic Search

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

S. Bekki

1995-01-01

230

CO 2 -Gaswechsel-Untersuchungen zur SO 2 -Resistenz von Flechten  

Microsoft Academic Search

The SO2 resistance of 12 lichen species with different growth forms and taken from different sites was investigated. The thalli were either exposed to different concentrations of SO2 gas (concentration at entry into the cuvette: 0.5; 1.0; 2.0 and 4.0 mg SO2\\/m3 air) or treated with Na2S2O5 solutions of differing concentration and pH. As a viability criterion the CO2 exchange

R. Rürk; V. Wirth; O. L. Lange

1974-01-01

231

Study of metal aerosol systems as a sink for atmospheric SO2  

Microsoft Academic Search

The chemical removal of SO2 in the presence of different aerosol systems has been investigated in laboratory experiments using a dynamic flow reactor. The aerosols consisted of wetted particles containing one of the following substances: MnCl2, Mn(NO3)2, MnSO4, CuCl2, Cu(NO3)2, CuSO4, FeCl3, NaCl. The SO2 removal rate R was measured as a function of the SO2 gas phase concentration (SO2)g,

Harald Berresheim; Wolfgang Jaeschke

1986-01-01

232

Adsorption of SO2 on bituminous coal char and activated carbon fiber  

USGS Publications Warehouse

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

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

1997-01-01

233

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, 2012 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part...

2012-07-01

234

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

...CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part...

2010-07-01

235

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

...CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part...

2011-07-01

236

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

Code of Federal Regulations, 2013 CFR

...CONTINUED) AIR PROGRAMS (CONTINUED) AMBIENT AIR MONITORING REFERENCE AND EQUIVALENT METHODS Procedures for Determining Comparability Between Candidate Methods and Reference Methods Pt. 53, Subpt. C, Fig. C-1 Figure C-1 to Subpart C of Part...

2013-07-01

237

What have we learned about global SO2 pollution with Aura/OMI data?  

NASA Astrophysics Data System (ADS)

Sulfur Dioxide (SO2) is a short-lived gas produced by volcanoes, power plants, refineries, metal smelting and general burning of fossil fuels. It is one of five EPA criteria pollutants. Emitted SO2 is soon converted to sulfate aerosol, with climate effects that include direct radiative forcing and aerosol-induced changes in cloud microphysics and the hydrological cycle. The Ozone Monitoring Instrument (OMI) launched on NASA Aura satellite in July 2004 offers unprecedented spatial resolution, coupled with contiguous daily global coverage, for space- based UV measurements of volcanic and anthropogenic SO2 emissions. Anthropogenic SO2 emissions in the PBL present challenges, because these typically weak signals need to be separated from the noise in the radiances. Plumes from strong surface sources of SO2 (such as smelters and coal burning power plants) and from strong regional pollution can currently be detected in the operational pixel data. Operational data were evaluated with in-situ aircraft SO2 profiles measured in the lower troposphere over China during the East-AIRE campaign in April 2005. This comparison demonstrates that OMI can distinguish between background SO2 conditions and heavy pollutions on a daily basis, suggesting potential of using OMI SO2 data for the regional pollution monitoring. Chinese SO2 pollution lofting above the PBL and long-range transport over Pacific Ocean was first confirmed using OMI data. Quantification of anthropogenic SO2 emissions requires off-line corrections of the average photon path, characterized by the operational air-mass factor (AMF). The AMF corrections in turn require a-priori information about the altitude of the SO2 plume center of mass, the total ozone, and surface albedo. In addition, aerosols and subpixel clouds affect the AMF in different ways depending on their amounts and vertical distribution. Therefore, ancillary cloud, snow and aerosol information available from near simultaneous A-train sensors is valuable in quantification of the OMI SO2 burdens. As an example the analysis of the effect of the major Chinese snow storm on the OMI SO2 data will be presented.Spatial smoothing and/or time averaging allow significant signal to noise enhancements. Applying these techniques, power plant emissions in Greece, Bulgaria, Turkey, and the US Ohio River valley as well emissions from Persian Gulf refineries, and plumes in an industrial complex near Mexico City can be seen in OMI data - several previously unknown sources have been detected. Using long-term averages, anthropogenic SO2 burdens can be compared directly in different parts of the world. On-going algorithm improvements such as spectral fitting will allow enhanced sensitivity to enable monitoring of a greater number of SO2 sources.

Krotkov, N.; Yang, K.; Bhartia, P. K.; Carn, S.; Krueger, A.; Dickerson, R.; Li, C.

2008-05-01

238

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

239

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

PubMed

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

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

2013-01-01

240

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.

241

SO(2N)/U(N) Riccati-Hartree-Bogoliubov Equation Based on the SO(2N) Lie Algebra of the Fermion Operators  

E-print Network

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

Seiya Nishiyama; Joao da Providencia

2014-07-04

242

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

EPA Science Inventory

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

243

PHYTOTOXICITY OF AIR POLLUTANTS. EVIDENCE FOR THE PHOTODETOXIFICATION OF SO2 BUT NOT O3  

EPA Science Inventory

Pisum sativum L. cv Alsweet (garden pea) and Lycopersicon esculentum flacca Mill. (tomato) were used to evaluate the phytotoxicity of SO2 and O3 in the light and dark. Plants were grown in controlled environment chambers and exposed to SO2 or O3 in the light or dark at the same e...

244

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...

245

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...

246

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

Microsoft Academic Search

A fire started at the Al-Mishraq State Sulfur plant near Mosul, Iraq on 24 June 2003 and burned for almost a month. Combustion of elemental sulfur in the fire produced dense clouds of sulfur dioxide (SO2) that were detected from space by the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) on 18 days. Estimated daily SO2 production from the

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

2004-01-01

247

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

E-print Network

THE SO2 ALLOWANCE TRADING SYSTEM: THE IRONIC HISTORY OF A GRAND POLICY EXPERIMENT Richard;1 The SO2 Allowance Trading System: The Ironic History of a Grand Policy Experiment Richard Schmalensee, it is ironic that cap-and-trade has come to be demonized by conservative politicians in recent years, since

Ford, Andrew

248

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

... TR SO2 Group 1 allowance allocations to new units. 97.612 Section 97.612 ...TR SO2 Group 1 allowance allocations to new units. (a) For each control period...Administrator will establish a separate new unit set-aside for the State for...

2014-07-01

249

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

... TR SO2 Group 2 allowance allocations to new units. 97.712 Section 97.712 ...TR SO2 Group 2 allowance allocations to new units. (a) For each control period...Administrator will establish a separate new unit set-aside for the State for...

2014-07-01

250

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...

251

40 CFR 73.19 - Certain units with declining SO2 rates.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Certain units with declining SO2 rates. 73.19 Section 73.19 Protection...Allowance Allocations § 73.19 Certain units with declining SO2 rates. (a) Eligibility. A unit is eligible for allowance...

2010-07-01

252

40 CFR 97.625 - Compliance with TR SO2 Group 1 assurance provisions.  

...SO2 Group 1 allowances for, such control period, the unit's allowable SO2 emission rate for such control period and, if such rate is expressed in lb per mmBtu, the unit's heat rate. (ii) By August 1 immediately after the...

2014-07-01

253

40 CFR 73.19 - Certain units with declining SO2 rates.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Certain units with declining SO2 rates. 73.19 Section 73.19 Protection...Allowance Allocations § 73.19 Certain units with declining SO2 rates. (a) Eligibility. A unit is eligible for allowance...

2011-07-01

254

40 CFR 97.725 - Compliance with TR SO2 Group 2 assurance provisions.  

...SO2 Group 2 allowances for, such control period, the unit's allowable SO2 emission rate for such control period and, if such rate is expressed in lb per mmBtu, the unit's heat rate. (ii) By August 1 immediately after the...

2014-07-01

255

40 CFR 73.19 - Certain units with declining SO2 rates.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Certain units with declining SO2 rates. 73.19 Section 73.19 Protection...Allowance Allocations § 73.19 Certain units with declining SO2 rates. (a) Eligibility. A unit is eligible for allowance...

2012-07-01

256

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

E-print Network

SO2 over central China: Measurements, numerical simulations and the tropospheric sulfur budget Hao sulfur budget - sources, sinks, transformation and transport. In April 2008, measured ambient SO2 was used to simulate sulfur chemistry, exhibiting reasonable agreement (r = 0.62, slope = 1

Dickerson, Russell R.

257

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

258

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

Code of Federal Regulations, 2011 CFR

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

2011-07-01

259

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

Code of Federal Regulations, 2013 CFR

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

2013-07-01

260

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

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Standards for sulfur dioxide (SO2). 60.43Da Section 60.43Da...Units § 60.43Da Standards for sulfur dioxide (SO2 ). (a) On and after...on a 24-hour basis. (d) Sulfur dioxide emissions are limited to 520...

2012-07-01

261

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standard for sulfur dioxide (SO2). 60.43Da Section 60.43Da...1978 § 60.43Da Standard for sulfur dioxide (SO2). (a) On and after...on a 24-hour basis. (d) Sulfur dioxide emissions are limited to 520...

2010-07-01

262

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

263

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

USGS Publications Warehouse

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

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

1998-01-01

264

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

NASA Astrophysics Data System (ADS)

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

Bekki, S.

1995-04-01

265

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

266

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

NASA Astrophysics Data System (ADS)

Ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of sulfur dioxide (SO2) have been performed at the Xianghe station (39.77°N, 117.0°E) located at ~50 km South-East of Beijing from March 2010 to February 2013. Tropospheric SO2 vertical profiles and corresponding vertical column densities (VCDs), retrieved by applying the Optimal Estimation Method to the MAX-DOAS observations, have been used to study the seasonal and diurnal cycles of SO2, in combination to correlative measurements from in situ instruments, as well as meteorological data. A marked seasonality is observed in both SO2 VCD and surface concentration, with a maximum in winter (February) and a minimum in summer (July). This can be explained by the larger emissions in winter due to the domestic heating and more favorable meteorological conditions for the accumulation of SO2 close to the ground during this period. Wind speed and direction are also found to be two key parameters in controlling the level of the SO2-related pollution at Xianghe. In the case of east or southwest wind, the SO2 concentration rises with the increase of the wind speed, since heavy polluting industries are located to the east and southwest of the station. In contrast, when wind comes from other directions, the stronger the wind, the less SO2 is observed. Regarding the diurnal cycle, the SO2 amount is larger in the early morning and late evening and lower at noon, in line with the diurnal variation of pollutant emissions and atmospheric stability. The observed diurnal cycles of MAX-DOAS SO2 surface concentration are also in very good agreement (correlation coefficient close to 0.9) with those from collocated in-situ data, demonstrating the reliability and robustness of our retrieval.

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

2014-05-01

267

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

NASA Astrophysics Data System (ADS)

Ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of sulfur dioxide (SO2) have been performed at the Xianghe station (39.75° N, 116.96° E) located at ~50 km southeast of Beijing from March 2010 to February 2013. Tropospheric SO2 vertical profiles and corresponding vertical column densities (VCDs), retrieved by applying the Optimal Estimation Method to the MAX-DOAS observations, have been used to study the seasonal and diurnal cycles of SO2, in combination to correlative measurements from in situ instruments, as well as meteorological data. A marked seasonality was observed in both SO2 VCD and surface concentration, with a maximum in winter (February) and a minimum in summer (July). This can be explained by the larger emissions in winter due to the domestic heating and more favorable meteorological conditions for the accumulation of SO2 close to the ground during this period. Wind speed and direction are also found to be two key factors in controlling the level of the SO2-related pollution at Xianghe. In the case of east or southwest wind, the SO2 concentration rises with the increase of the wind speed, since heavy polluting industries are located to the east and southwest of the station. In contrast, when wind comes from other directions, the stronger the wind, the less SO2 is observed. Regarding the diurnal cycle, the SO2 amount is larger in the early morning and late evening and lower at noon, in line with the diurnal variation of pollutant emissions and atmospheric stability. The observed diurnal cycles of MAX-DOAS SO2 surface concentration are also in very good agreement (correlation coefficient close to 0.9) with those from collocated in-situ data, demonstrating the reliability and robustness of our retrieval.

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

2014-03-01

268

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

PubMed

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

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

2013-07-16

269

SO2 capture by guanidinium-based ionic liquids: a theoretical study.  

PubMed

Ionic liquids (ILs) show good performances in SO(2) separation science, e.g., SO(2) capture from high-temperature flue gas or separation from gas mixtures. In this work, the mechanism of capturing SO(2) by three guanidinium-based ILs, 1,1,3,3-tetramethylguanidinium lactate ([tmgHH][L]), 1,1,3,3-tetramethylguanidinium bis(trifluoromethylsulfonyl)imide ([tmgHH][Tf(2)N]), and 1,1,3,3-tetramethylguanidinium tetrafluoroborate ([tmgHH][BF(4)]), is investigated by using molecular dynamic simulation and ab initio calculation. The results of condensed phase molecular dynamic simulation for the mixtures of SO(2) and these three ILs indicate the similar SO(2) organization and interaction among them; SO(2) may organize around [tmgHH](+) while it favorably organizes around the anions through Lewis acid-base interaction. Gas phase ab initio calculations show that [tmgHH][L] chemically interacts with SO(2) while [tmgHH][Tf(2)N] and [tmgHH][BF(4)] do not, which is supported by the earlier FT-IR and (1)H NMR data and is also consistent with the experimental result of a much higher absorption capability of [tmgHH][L] for SO(2) than the latter two. The anion plays a key role in the chemical interaction between [tmgHH][L] and SO(2), the S atom is bonded to the N atom on -NH(2) of [tmgHH](+), and some products with aminosulfate or aminosulfinic acid fragment may be formed. This work shows that IL structures should be carefully tailored for their final application in SO(2) capture. PMID:21410280

Yu, Guangren; Chen, Xiaochun

2011-04-01

270

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

271

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

272

Greenhouse Gases  

NSDL National Science Digital Library

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

273

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

274

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

NASA Astrophysics Data System (ADS)

Volcanic ash and sulphur dioxide masses from the November 2005 eruption of Karthala volcano, Comoros Islands, are simultaneously retrieved using rapid-scan, multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite. Retrievals are made every 15 min, which show that the ash and SO2 separate in the vertically sheared atmosphere producing a fast moving upper level (~12 km) SO2 cloud, a slower moving middle level (~8 km) ash cloud and a boundary layer (<3 km) SO2 plume. The total mass of fine ash is 0.1 +/- 0.05 Tg (SiO2), the upper level SO2 mass is 0.19 +/- 0.01 Tg (S) while the boundary layer SO2 mass is 0.009 +/- 0.01 Tg (S). These are the first simultaneous satellite measurements of ash and SO2 from an erupting volcano and confirm previous ideas about vertical separation. We suggest care must be exercised when using SO2 as a tracer for volcanic ash in aviation hazard warning systems.

Prata, A. J.; Kerkmann, J.

2007-03-01

275

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

USGS Publications Warehouse

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

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

2006-01-01

276

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

USGS Publications Warehouse

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

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

1997-01-01

277

Gas-phase ion chemistry of NF3/SO2 mixtures  

NASA Astrophysics Data System (ADS)

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

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

2007-10-01

278

Lessons Learned from OMI Observations of Point Source SO2 Pollution  

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

279

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

280

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

281

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

282

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

SciTech Connect

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

Hsu, S.A.

1995-04-01

283

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

NASA Astrophysics Data System (ADS)

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

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

2012-06-01

284

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

285

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

286

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

287

Measurement of sulfur isotope compositions by tunable laser spectroscopy of SO2.  

PubMed

Sulfur isotope measurements offer comprehensive information on the origin and history of natural materials. Tunable laser spectroscopy is a powerful analytical technique for isotope analysis that has proven itself readily adaptable for in situ terrestrial and planetary measurements. Measurements of delta(34)S in SO2 were made using tunable laser spectroscopy of combusted gas samples from six sulfur-bearing solids with delta(34)S ranging from -34 to +22 per thousand (also measured with mass spectrometry). Standard deviation between laser and mass spectrometer measurements was 3.7 per thousand for sample sizes of 200 +/- 75 nmol SO(2). Although SO(2)(g) decreased 9% over 15 min upon entrainment in the analysis cell from wall uptake, observed fractionation was insignificant (+0.2 +/- 0.6 per thousand). We also describe a strong, distinct (33)SO(2) rovibrational transition in the same spectral region, which may enable simultaneous delta(34)S and Delta(33)S measurements. PMID:18020312

Christensen, Lance E; Brunner, Benjamin; Truong, Kasey N; Mielke, Randall E; Webster, Christopher R; Coleman, Max

2007-12-15

288

BrO/SO2 ratios at Popocatepetl volcano during increased activity in 2012  

NASA Astrophysics Data System (ADS)

Since its reactivation in 1994 after many decades of inactivity, Popocatepetl volcano has been showing long periods of quiescent degassing and some events of intensified activity in connection with dome building and destruction processes. During a period of increased activity of the volcano, which began in April 2012, mobile ultraviolet DOAS measurements and stationary DOAS scans were performed to quantify SO2 fluxes and BrO/SO2 ratios within the volcanic plume. The results of these measurements are presented in the context of the volcanic activity, which consisted of increased emission of gas and ash and Vulcanian type explosions. In general, SO2 emissions were high during the period April-June 2012 and so the BrO emissions, however, the BrO/SO2 ratios did not change strongly before, during and after the increased activity.

Fickel, M.; Delgado Granados, H.

2012-12-01

289

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

E-print Network

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

Schmalensee, Richard

290

On Io's 2.788-micron band: Origin by SO2 or H2O?  

NASA Technical Reports Server (NTRS)

Laboratory reflectance spectra of SO2 frost and ice and thin H2O frost show that the recently reported band at 2.788 microns in Io's disk-integrated spectrum can be qualitatively explained by the presence of solid SO2 on Io's surface. However, the reported width of the Io band is too great to be explained by SO2 frost or ice alone. Lab spectra presented here, and other data cited here, show clearly that solid SO2 has a strong band at 2.789 microns, and that Io should have such a band. These results do not support the claim of Bregman et al. that H2O is the primary cause of the Io band.

Nash, Douglas B.

1994-01-01

291

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...

292

40 CFR 74.24 - Current allowable SO2 emissions rate.  

Code of Federal Regulations, 2010 CFR

...74.24 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) SULFUR DIOXIDE OPT-INS Allowance Calculations for Combustion Sources § 74.24 Current allowable SO2 emissions rate....

2010-07-01

293

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

E-print Network

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

Nam, Kyung-Min

2012-10-01

294

Use of Motion Estimation Algorithms for Improved Flux Measurements Using SO 2 Cameras  

E-print Network

the correctivethms for improved flux measurements using SO2 cameras, J. Volcanol. ATHAM DT-CWT Farneback 2:3 1 2 3 4 5 6 flu x (kg s ? 1 ) Flux ATHAM DT-CWT Farneback 0 10 -7 10 -5 10 -3 10 -1 SO 2 m g k ( 2 - ) 4 N. Peters et al. / Journal of Volcanology... :03:00 08:04:00 08:0 Simulati 2 0 2 4 6 8 10 12 SO 2 flu x (kg s ? 1 ) Flu ATHAM DT-CWT Farneback Fig. 4. Summary of results from the “open-top” ATHAM simulation. SO2 fluxes calculated u plotted against time. Snapshots of the velocity fields...

Peters, N.; Hoffmann, A.; Barnie, T.; Herzog, M.; Oppenheimer, C.

2014-01-01

295

Dissociation dynamics of the methylsulfonyl radical and its photolytic precursor CH3SO2Cl  

E-print Network

- pogenic source of SO2 is the combustion of sulfur-containing fossil fuels, the major natural sources of SO the endoergicity. Hence, a statistical recoil kinetic energy distribution should and does fit the distribution

Butler, Laurie J.

296

RESEARCH ARTICLE Open Access A 50-year record of NOx and SO2 sources in  

E-print Network

. Introduction The chemical quality of snowfall deposited in high-eleva- tion areas in the Rocky Mountain region in the western United States have indicated an increase in total N deposition and a decrease in SO2- 4 deposition

297

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

NASA Astrophysics Data System (ADS)

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

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

2009-12-01

298

An integrated study of SO2 degassing from Tungurahua volcano, Ecuador  

NASA Astrophysics Data System (ADS)

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

McCormick, B. T.; Yang, J.; Edmonds, M.; Mather, T. A.; Carn, S. A.; Hidalgo, S.; Langmann, B.; Herzog, M.

2012-12-01

299

Yield response curves of crops exposed to SO 2 time series  

NASA Astrophysics Data System (ADS)

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

Male, Larry; Preston, Eric; Neely, Grady

300

SIMULTANEOUS ABSORPTION AND OXIDATION OF NO AND SO2 BY AQUEOUS SOLUTIONS OF SODIUM CHLORITE  

Microsoft Academic Search

Complete and simultaneous removal of NO and SO2 is achieved in a laboratory bubble column reactor at about room temperature using aqueous solutions of NaClO2 buffered with Na2HPO4and KH2PO4The influence of reaction medium chemistry (pH and concentrations of buffer and NaOH) on NOx and SO2 removal efficiencies was also evaluated. The buffered NaClO2 solution is determined to be more effective

YUSUF G. ADEWUYI; XIANGDONG HE; HENRY SHAW; WANNA LOLERTPIHOP

1999-01-01

301

Self, Air, and Nitrogen-Broadening in the ? 1Band of SO 2  

Microsoft Academic Search

The collisional line broadening of SO2transitions in the ?1band was measured with SO2, air, and nitrogen as perturbers by applying a diode laser spectrometer in pulse mode. Eighteen lines from thePbranch (5 ?J? ? 44, 0 ?[formula]? 20), eight lines from theQbranch (10 ?J? ? 40, 1 ?[formula]? 23), and five lines from theRbranch (12 ?J? ? 35, 4 ?[formula]?

B. Sumpf; O. Fleischmann; H.-D. Kronfeldt

1996-01-01

302

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

PubMed

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

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

2014-10-01

303

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

PubMed Central

The effects of SO2 on stomatal aperture of attached sunflower leaves were observed with a remote-control light microscope system that permitted continuous observation of stomatal responses over periods of several hours. The relationship between actual stomatal aperture and stomatal conductance, measured with a porometer, also was examined on leaves before and after exposure to SO2. A distinction between uninjured and injured regions was clearly visible on leaves after exposure to 1.5 microliters per liter SO2 for less than an hour. During the exposure, the mean value of apertures for many stomata, which indicates stomatal conductance and transpiration rate, tended to decrease simultaneously in the uninjured and injured regions. However, the rate of decrease in the injured region was slower than that in the uninjured region because of a transient opening induced by water-soaking in the injured region. The transient opening was less common in stomata near veins and veinlets. There was a good correlation between pore width and stomatal conductance measured with a porometer before exposure to SO2. This correlation continued in leaves exposed to SO2 until visible, irreversible injury occurred, but then it disappeared. The results of these experiments indicate the necessity of continuous observation of individual stomata under the microscope to understand the effects of air pollutants such as SO2 on stomatal behavior. Images Fig. 3 Fig. 5 PMID:16664361

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

1985-01-01

304

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

305

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

306

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

307

Identification of Large Emission Sources of SO2 in Mexico Megacity  

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

308

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

USGS Publications Warehouse

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

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

1996-01-01

309

Interspecific Variation in SO(2) Flux : Leaf Surface versus Internal Flux, and Components of Leaf Conductance.  

PubMed

The objective of this study was to clarify the relationships among stomatal, residual, and epidermal conductances in determining the flux of SO(2) air pollution to leaves. Variations in leaf SO(2) and H(2)O 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) SO(2) 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 SO(2), and 0.3 to 1.3 millimoles per square meter per second for H(2)O vapor. Flux of SO(2) into leaves through stomata ranged from approximately 0 to 8.5 (dark) and 3.8 to 16.0 (light) millimoles per square meter per second. Flux of H(2)O vapor from leaves through stomata ranged from approximately 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 SO(2) and H(2)O vapor over twice as high as for the other species. Stomatal conductance based on H(2)O vapor flux averaged from 0.07 to 0.13 mole per square meter per second among the four species. Internal conductance of SO(2) as calculated from SO(2) 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, SO(2) flux could be predicted from stomatal conductance for H(2)O 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 SO(2) flux. PMID:16664551

Olszyk, D M; Tingey, D T

1985-12-01

310

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

NASA Astrophysics Data System (ADS)

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

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

311

Measurements of HNO3, SO2 High Resolution Aerosol SO4 (sup 2-), and Selected Aerosol Species Aboard the NASA DC-8 Aircraft: During the Transport and Chemical Evolution Over the Pacific Airborne Mission (TRACE-P).  

National Technical Information Service (NTIS)

The UNH investigation during TRACE-P provided measurements of selected acidic gases and aerosol species aboard the NASA DC-8 research aircraft. Our investigation focused on measuring HNO3, SO2, and fine (less than 2 microns) aerosol SO4(sup 2-) with two m...

R. W. Talbot, J. E. Dibb

2004-01-01

312

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

NASA Astrophysics Data System (ADS)

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

Burton, Michael; Sawyer, Georgina

2013-04-01

313

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

314

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

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

315

Observing the plume of Popocatepetl with a novel SO2-Camera  

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

316

An integrated study of SO2 degassing from Tungurahua volcano, Ecuador  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

317

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

NASA Astrophysics Data System (ADS)

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

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

318

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

319

Induced Interaction between Polypyrrole and SO2 via Molecular Sieve 13X  

NASA Astrophysics Data System (ADS)

Electrical conductivity sensitivity and interaction mechanisms between polypyrrole(Ppy)/molecular sieve 13X composites and CO2, CO, and SO2 were investigated. Polypyrrole was synthesized and composites were fabricated from dry mixing and dispersing zeolite particles into the Ppy matrix particles, and followed by compressing into a pellet form. Effects of zeolite concentration, cation type, and cation concentration were investigated. The electrical conductivity in air of Ppy doped with naphthalene-2-sulfonic acid(?) sodium salt increased monotonically with the doping level. There were negligible negative electrical conductivity responses of Ppy and its composites when exposed to CO2, and CO in contrast to definite positive responses towards SO2 in which the interaction was irreversible. Undoped Ppy and doped Ppy composites at 10% v/v of zeolite13X content possessed the highest sensitivity to SO2; beyond this volume fraction the sensitivity was reduced with increasing molecular sieve 13X content. The composites of unmodified 13X, with Na^+ fully present within its cavity, gave the greatest electrical conductivity sensitivity towards SO2. The sensitivity of Ppy/13X composite to SO2 diminished when the cation Na^+ was exchanged to other alkali cations in this decreasing order: Cs^+, K^+, and Li^+.

Soontornworajit, Boonchoy; Sirivat, Anuvat

2006-03-01

320

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

321

Attenuated Mycobacterium tuberculosis SO2 Vaccine Candidate Is Unable to Induce Cell Death  

PubMed Central

It has been proposed that Mycobacterium tuberculosis virulent strains inhibit apoptosis and trigger cell death by necrosis of host macrophages to evade innate immunity, while non-virulent strains induce typical apoptosis activating a protective host response. As part of the characterization of a novel tuberculosis vaccine candidate, the M. tuberculosis phoP mutant SO2, we sought to evaluate its potential to induce host cell death. The parental M. tuberculosis MT103 strain and the current vaccine against tuberculosis Bacillus Calmette-Guérin (BCG) were used as comparators in mouse models in vitro and in vivo. Our data reveal that attenuated SO2 was unable to induce apoptotic events neither in mouse macrophages in vitro nor during lung infection in vivo. In contrast, virulent MT103 triggers typical apoptotic events with phosphatidylserine exposure, caspase-3 activation and nuclear condensation and fragmentation. BCG strain behaved like SO2 and did not induce apoptosis. A clonogenic survival assay confirmed that viability of BCG- or SO2-infected macrophages was unaffected. Our results discard apoptosis as the protective mechanism induced by SO2 vaccine and provide evidence for positive correlation between classical apoptosis induction and virulent strains, suggesting apoptosis as a possible virulence determinant during M. tuberculosis infection. PMID:23028853

Monzon, Marta; Badiola, Juan J.; de Martino, Alba; Ferrer, Nadia; Marinova, Dessislava; Anel, Alberto; Martin, Carlos; Pardo, Julian

2012-01-01

322

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

323

SO2 protects the amino nitrogen metabolism of Saccharomyces cerevisiae under thermal stress  

PubMed Central

Summary Thermal stress conditions during alcoholic fermentation modify yeasts' plasma membrane since they become more hyperfluid, which results in a loss of bilayer integrity. In this study, the influence of elevated temperatures on nitrogen metabolism of a Saccharomyces cerevisiae strain was studied, as well as the effect of different concentrations of SO2 on nitrogen metabolism under thermal stress conditions. The results obtained revealed that amino nitrogen consumption was lower in the fermentation sample subjected to thermal stress than in the control, and differences in amino acid consumption preferences were also detected, especially at the beginning of the fermentation. Under thermal stress conditions, among the three doses of SO2 studied (0, 35, 70?mg?l?1 SO2), the highest dose was observed to favour amino acid utilization during the fermentative process, whereas sugar consumption presented higher rates at medium doses. PMID:22452834

Ancin-Azpilicueta, Carmen; Barriuso-Esteban, Blanca; Nieto-Rojo, Rodrigo; Aristizabal-Lopez, Nerea

2012-01-01

324

Health risks of short-term SO2 exposure to exercising asthmatics.  

PubMed

A method is described for quantifying health risks to asthmatics briefly exposed to elevated levels of SO2. By combining symptomological and physiological measurements, we have developed a dose-response surface that relates both severity and incidence of response to ambient air quality levels. The complete model to assess potentially avoidable risks includes power plant emission data; ambient SO2 background levels; demographic and activity patterns of asthmatics, the identified population at risk; and the dose-response surface. The estimated annual risk to persons experiencing an SO2-induced response due to a nearby power plant is quite small (response rates under 3 percent). Uncertainties due to modeling errors, variations in activity patterns, demographics and physiological response are discussed. PMID:2754441

Freudenthal, P C; Roth, H D; Hammerstrom, T; Lichtenstein, C; Wyzga, R E

1989-06-01

325

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

NASA Astrophysics Data System (ADS)

The anthropogenic emissions of SO 2 and NO x 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 SO 2 emissions in these parts of Asia have been calculated to be 18.3 and 29.1 Tg in 1975 and 1987, respectively. The calculated total NO x emissions were 9.4 and 15.5 Tg in 1975 and 1987, respectively. The SO 2 and NO x emissions in East Asia (China, Japan, South Korea, North Korea and Taiwan) were 23.4 and 10.7 Tg in 1975 and 1987, respectively. Keyword: Emission inventories, sulfur dioxide emissions, nitrogen oxide emissions, Asian emissions, anthropogenic emissions.

Kato, Nobuo; Akimoto, Hajime

326

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

NASA Astrophysics Data System (ADS)

The anthropogenic emissions of SO 2 and NO x for 25 Asian countries east of Afghanistan and Pakistan have been calculated for 1975, 1980, 1986, 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 SO 2 emissions in these parts of Asia have been calculated to be 18.3 and 29.1 Tg in 1975 and 1987, respectively. The calculated total NO x emissions were 9.4 and 15.5 Tg in 1975 and 1987, respectively. The SO 2 and NO x emissions in East Asia (China, Japan, South Korea, North Korea and Taiwan) were 23.4 and 10.7 Tg in 1975 and 1987, respectively.

Kato, Nobuo; Akimoto, Hajime

327

SO2 monitoring above Venus' clouds using VEx/SPICAV-UV nadir observations  

NASA Astrophysics Data System (ADS)

SO2 in the upper atmosphere of Venus is an important tracer of (i) its recent (within 10 million years) geological activity, (ii) the chemistry and photo-chemistry of sulfur-bearing species, including H2SO4-H2O underlying clouds and (iii) general circulation of the atmosphere bringing SO2-rich air up to levels where photo-chemical destruction occurs. The first monitoring, using Pioneer Venus and ground-based data, showed a two order-of-magnitude decrease from 1980 to 1995 [Esposito et al., 1988]. Latitudinal variations were also constrained in the early 1990s, and exhibited an increasing observable SO2 column density with increasing latitude [Zasova et al., 1993; Na et al., 1994]. Measurements of SO2 have resumed since 2006 mainly thanks to SPICAV/SOIR instrument on-board Venus Express, and first studies showed an opposite latitudinal gradient as well as relatively high SO2 abundance, comparable to the early 1980s [Belyaev et al., 2008; Marcq et al., 2011]. Here we show the results for the 2007-2010 epoch, using an improved version of Marcq et al.'s (2011) model able to cope with non-nadir observations. Strong variability is observed within short (daily) timescales , but there is evidence for two distinct regimes, the most frequent being identical to the situation in 2006 already published (rather high abundances, negative latitudinal gradient), but starting in late 2009, a new regime very similar to the situation during the early 1990s (low abundances, positive latitudinal gradients) has been observed, alternating with the common regime within a few Earth months. Simple modeling suggests that fluctuations in the general circulation and/or sporadic change in SO2 below 65 km may cause the alternation between both regimes. Bibliography: Esposito et al., JGR 93 (1988) Zasova et al., Icarus 105 (1993) Na et al., Icarus 112 (1994) Belyaev et al., JGR 113 (2008) Marcq et al., Icarus 211 (2011)

Marcq, E.; Montmessin, F.; Bertaux, J. L.; Belyaev, D.; Fedorova, A.

2012-04-01

328

TOMS and Volcanic SO2: an Important aid to the Understanding of Volcanism and the Atmosphere  

NASA Astrophysics Data System (ADS)

It is impossible to measure gas fluxes from the ground in a major volcanic event, but the TOMS instrument provided the first quantitative measurements of individual stratospheric eruptions, because SO2 could be measured as well as O3. The measurements were quickly noticed by scientists, because the masses of sulfur erupted often far exceeded what they expected to find, based on petrology and its supposed constraints, by surprising factors of 10 to 100. This result is still not well understood, and is an important driving idea for volcanologic research. TOMS was applied globally and the explosive volcanic flux of SO2 to the atmosphere was compiled for the first time using direct measurements --an important input to earth systems analysis. Comparison of TOMS volcanic cloud SO2 maps with infrared volcanic ash cloud maps showed that there is often spatial separation of gas-rich volcanic clouds emplaced higher in the atmosphere and ash-rich clouds which are lower and which drift in different directions because of windshears. Sequential examination of TOMS data showed that SO2 masses in volcanic clouds increases for 24 hours or more after eruption. The best explanation of this increase is that ice which forms early in volcanic clouds captures SO2 which is then released again as the stratospheric ice sublimes. The presentation will document all of the best examples of the discoveries listed above. Volcanologists and those interested in the mitigation of volcanic cloud hazards have repeatedly suggested that geostationary SO2 and ash sensing capability at higher spatial resolution would provide important new science opportunities. The sensors of the next remote sensing era (MODIS, ASTER, SEVIRI, OMI, ABI) bring us closer to achieving these goals.

Rose, W. I.; Bluth, G. J.

2003-12-01

329

Massive volcanic SO(2) oxidation and sulphate aerosol deposition in Cenozoic North America.  

PubMed

Volcanic eruptions release a large amount of sulphur dioxide (SO(2)) into the atmosphere. SO(2) is oxidized to sulphate and can subsequently form sulphate aerosol, which can affect the Earth's radiation balance, biologic productivity and high-altitude ozone concentrations, as is evident from recent volcanic eruptions. SO(2) oxidation can occur via several different pathways that depend on its flux and the atmospheric conditions. An investigation into how SO(2) is oxidized to sulphate-the oxidation product preserved in the rock record-can therefore shed light on past volcanic eruptions and atmospheric conditions. Here we use sulphur and triple oxygen isotope measurements of atmospheric sulphate extracted from tuffaceous deposits to investigate the specific oxidation pathways from which the sulphate was formed. We find that seven eruption-related sulphate aerosol deposition events have occurred during the mid-Cenozoic era (34 to 7 million years ago) in the northern High Plains, North America. Two extensively sampled ash beds display a similar sulphate mixing pattern that has two distinct atmospheric secondary sulphates. A three-dimensional atmospheric sulphur chemistry and transport model study reveals that the observed, isotopically discrete sulphates in sediments can be produced only in initially alkaline cloudwater that favours an ozone-dominated SO(2) oxidation pathway in the troposphere. Our finding suggests that, in contrast to the weakly acidic conditions today, cloudwater in the northern High Plains may frequently have been alkaline during the mid-Cenozoic era. We propose that atmospheric secondary sulphate preserved in continental deposits represents an unexploited geological archive for atmospheric SO(2) oxidation chemistry linked to volcanism and atmospheric conditions in the past. PMID:20559384

Bao, Huiming; Yu, Shaocai; Tong, Daniel Q

2010-06-17

330

Distribution of PM 2.5, acidic and basic gases near highway in central Taiwan  

NASA Astrophysics Data System (ADS)

Particulate PM 2.5 and acidic gas samples were collected during two successive sampling periods at two different sampling sites namely, Nantou (near highway site) and Erlin (far highway site) of central Taiwan region. The distribution of PM 2.5, acidic and basic gases was assessed simultaneously in both the sampling sites using annual denuder system. Chemical species of PM 2.5 analyzed included NO 3-, SO 42-, NH 4+, Cl -, Ca 2+, K + and Na + and gaseous HNO 2, HNO 3, HCl, SO 2 and NH 3. Data on NO, NO 2, CO and meteorological parameters were obtained from air quality monitoring station, Environmental Protection Agency (EPA), Taiwan. Time-weighted mean concentration model was used to investigate the pollutant sources. In addition, formation of nitrate aerosols from NO 2 was discussed. The PM 2.5 concentrations were 41.1 and 32.9 ?g m - 3 at near and far highway sites respectively. The average concentration of three main ionic species SO 42-, NO 3- and NH 4+ accounted to 44% for PM 2.5 indicating that the formation was mainly via secondary process. The PM 2.5, HNO 3, NO 3-, NO, NO 2 and CO were highest at near highway site compared to far highway site. Based on the results of this study we conclude that, higher traffic emissions coupled with poor ventilation due to topography of the area caused increased HNO 3, NO 3-, NO, NO 2 and CO concentrations in near highway site.

Horng, Chuen-Liang; Cheng, Man-Ting

2008-04-01

331

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

332

A Markov chain model for the mean daily SO2 concentrations  

NASA Astrophysics Data System (ADS)

This paper is concerned with the study of Markov dependence of a SO 2 concentration series (daily means) measured over an industrial zone. A two state chain is used obtained by classifying the concentrations as to a given threshold (1: C ? Cthres:2- C > Cthres) and the order of the Markov chain is studied as a function of the Cther: particular emphasis is laid on the study of Cther = 250 ?gm-3 (the 24-h concentration standard for SO 2 in Romania). Beside the study of Markov dependence, we use the Besson coefficient and the informational entropy as dependence indices.

Romanof, Nicolae

333

IO - Could SO2 condensation/sublimation cause the sometimes reported post-eclipse brightening  

NASA Astrophysics Data System (ADS)

It is shown that each of the three quantifiable brightening characteristics (i.e., amplitude, time-scale /half-life/, and temporal variability) suggests that brightening of Io may be due to condensation and sublimation of SO2 frost. This is concentrated within a region that encompasses both the subsolar points at the time of entrance into and emergence from eclipse, and volcanic sources. Qualitatively and intuitively, an SO2 frost hypothesis is found to provide good possibilities for explaining any variations in Io's ability to brighten, which may occur on a time scale of years.

Fanale, F. P.; Banerdt, W. B.; Cruikshank, D. P.

1981-06-01

334

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

335

IO - Could SO2 condensation/sublimation cause the sometimes reported post-eclipse brightening  

NASA Technical Reports Server (NTRS)

It is shown that each of the three quantifiable brightening characteristics (i.e., amplitude, time-scale /half-life/, and temporal variability) suggests that brightening of Io may be due to condensation and sublimation of SO2 frost. This is concentrated within a region that encompasses both the subsolar points at the time of entrance into and emergence from eclipse, and volcanic sources. Qualitatively and intuitively, an SO2 frost hypothesis is found to provide good possibilities for explaining any variations in Io's ability to brighten, which may occur on a time scale of years.

Fanale, F. P.; Cruikshank, D. P.; Banerdt, W. B.

1981-01-01

336

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

337

A visible DNA-protein stain: Feulgen-Pararosanilin(SO2) Light Green.  

PubMed

Feulgen-Pararosanilin(SO2) Light Green, a DNA-protein stain, is described that is suited both for visual analysis and quantitative cytochemical measurement. The stain has been applied on cervical cells and quantitative aspects have been studied on chicken erythrocyte and rat liver nuclei. In comparison to single staining, the Feulgen-Pararosanilin(SO2) DNA content of the nuclei remains unaltered after application of the combined staining. The Light Green protein content is reduced considerably, however, dependent on the degree of chromatin condensation in the nucleus. PMID:2422687

Oud, P S; Pahlplatz, M M; Hermkens, H G; Tas, J; James, J; Vooijs, G P

1986-01-01

338

Predicting SO2 pollution incidents by means of additive models with optimum variable selection  

NASA Astrophysics Data System (ADS)

The aim of this paper is to predict time series of SO2 concentrations emitted by coal-fired power stations in order to estimate in advance emission episodes and analyze the influence of some meteorological variables in the prediction. An emission episode is said to occur when the series of bi-hourly means of SO2 is greater than a specific level. For coal-fired power stations it is essential to predict emission episodes sufficiently in advance so appropriate preventive measures can be taken. We proposed a methodology to predict SO2 emission episodes based on using an additive model and an algorithm for variable selection. The methodology was applied to the estimation of SO2 emissions registered in sampling locations near a coal-fired power station located in Northern Spain. The results obtained indicate a good performance of the model considering only two terms of the time series and that the inclusion of the meteorological variables in the model is not significant.

Sestelo, Marta; Roca-Pardiñas, Javier; Ordóñez, Celestino

2014-10-01

339

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

Microsoft Academic Search

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

A. J. Prata; J. Kerkmann

2007-01-01

340

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.

341

A XPS investigation of SO 2 adsorption on ceria-zirconia mixed-metal oxides  

NASA Astrophysics Data System (ADS)

The interaction between ceria-zirconia mixed-metal oxide model catalysts and SO 2 was studied using X-ray photoelectron spectroscopy (XPS). An in situ reaction cell was employed to expose the polycrystalline ceria-zirconia mixed-metal oxide catalyst wafers to various partial pressures of SO 2 at elevated temperatures. Six compositions of CeO 2/ZrO 2 solid solutions were examined in this study, which include CeO 2/ZrO 2 molar ratios of 1:0, 9:1, 7:3, 5:5, 2:8, and 0:1. The samples were exposed to SO 2 at temperatures from 298 to 873 K and pressures reaching 1000 Torr. XPS results show an increased adsorption of SO 2 at either elevated temperatures or higher ceria mole fractions. Additionally, both a sulfate (SO 4) and sulfite (SO 3) surface species were identified. No significant change in sulfate-to-sulfite ratio as a function of temperature, exposure pressure, or composition was observed under the conditions of this study. However, surface hydroxyl functionalization was found to play an important role in the adsorption of sulfur dioxide on the materials studied.

Romano, Esteban J.; Schulz, Kirk H.

2005-06-01

342

Effect of SO2 and bisulfite on heterotrophic activity in an acid soil.  

PubMed Central

Glucose oxidation was inhibited in a forest soil (pH 4.01) previously exposed by 1.0 microliter of SO2 per liter, the extent of inhibition and the decline in pH being directly related to the length of exposure. The phase of rapid CO2 evolution in protein hydrolysate-amended soil previously treated with 5.0 microliter of SO2 per liter for 24 h or 1.0 microliter/liter for 48 h was delayed, but the degradation of the amino acid mixture then proceeded rapidly. Bacterial numbers in soil incubated for 48 h with 1.0 microliter of SO2 per liter were reduced, but the bacteria grew rapidly if glucose or an amino acid mixture was added after the exposure period. Low levels of bisulfite inhibited amino acid decomposition in soil at pH 3.89, but the effect was less pronounced in soil at pH 4.01. Comparable levels of sulfate were not toxic to carbon mineralization. Approximately 1.0 microgram of bisulfite S and about 20 microgram of sulfate S per g of soil appeared when the soil was treated with 1.0 microliter of SO2 per liter for 48 h. Bisulfite added to the soil disappeared readily. The possible ecological significance of the findings is discussed. PMID:39507

Grant, I F; Bancroft, K; Alexander, M

1979-01-01

343

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

E-print Network

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

Rose, William I.

344

40 CFR 75.11 - Specific provisions for monitoring SO2 emissions.  

Code of Federal Regulations, 2010 CFR

...Monitoring Provisions § 75.11 Specific provisions for monitoring SO2...Report the appropriate fuel-specific default moisture value for...monitor to measure the unit heat input rate shall, during any...into Equation F-23 the hourly heat input, calculated using...

2010-07-01

345

TEMPERATURE DEPENDENCE OF MASS ACCOMMODATION OF SO2 AND H2O2 ON AQUEOUS SURFACES  

EPA Science Inventory

The mass accommodation coefficient of SO2 and H2o2 on aqueos surfaces over the temperature range 260 - 292oK are reported. he experimental method used combined a monodisperse train of droplets and a low pressure flow reactor. ptake rates were determined by measuring changes in tr...

346

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...

347

SO2 CONCENTRATION ESTIMATES FOR NEW YORK CITY, 1880-1980  

EPA Science Inventory

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

348

Three-body dissociation dynamics of SO23 studied through dissociative photodetachment of SO2  

E-print Network

photoelectron­photofrag- ment coincidence (PPC) spectroscopy and found evidence for an S­O bound dimer within of these clusters. PPC spectroscopy has been shown to be a use- ful method for studying the energetics and dy- namics of small clusters [12]. For ðSO2�� 3 , PPC spectroscopy will be used to study the dissociation

Continetti, Robert E.

349

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

Microsoft Academic Search

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.

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

2008-01-01

350

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

EPA Science Inventory

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

351

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...

352

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...

353

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

EPA Science Inventory

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

354

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...

355

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...

356

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...

357

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 ...

358

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...

359

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 ...

360

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...

361

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...

362

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...

363

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...

364

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 ...

365

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...

366

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...

367

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...

368

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

E-print Network

atmosphere was necessary in order to keep28 early Mars warm and wet. However, current models have not been a significant formation of sulfate37 minerals during the Noachian and inhibiting carbonates from forming of episodic warm47 episodes facilitated by the release of SO2 to the atmosphere. These episodes could explain

Boyer, Edmond

369

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...

370

SORBENT/UREA SLURRY INJECTION FOR SIMULTANEOUS SO2/NOX REMOVAL  

EPA Science Inventory

The combination of sorbent injection and selective noncatalytic reduction (SNCR) technologies has been investigated for simulataneous SO2/NOx removal. A slurry composed of a urea-based solution and various Ca-based sorbents was injected at a range of tempera...

371

IDENTIFICATION OF CASO4 FORMED BY REACTION OF CAO AND SO2  

EPA Science Inventory

The injection of calcium-based sorbents into coal-fired boilers for reaction with, and reduction in the levels of, sulfur dioxide (SO2) in the flue gas has undergone considerable research and development. Significant effort has also been made in developing models for the overall ...

372

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...

373

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

EPA Science Inventory

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

374

Regional climate responses to geoengineering with tropical and Arctic SO2 injections  

E-print Network

Regional climate responses to geoengineering with tropical and Arctic SO2 injections Alan Robock,1 insolation and cool Earth, has been suggested as an emergency response to geoengineer the planet in response aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone

Robock, Alan

375

SO2 classification for air quality levels estimation using artificial intelligent techniques  

Microsoft Academic Search

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

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

2006-01-01

376

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

377

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

NASA Technical Reports Server (NTRS)

Calculations based on the atom superposition and electron delocalization molecular orbital technique suggest that O2 will adsorb preferentially end-on at an angle 45 deg from normal on a nickel cation site on the (100) surface of NiO. SO2 adsorption is also stronger on the nickel site; SO2 bonds through the sulfur atom in a plane perpendicular to the surface. Adsorption energies for SO3 on the nickel and oxygen sites are comparable in the preferred orientation in which the SO3 plane is parallel to the surface. The calculations suggest that the strength of adsorption varies as O2 greater than SO2 greater than SO3. On activation, SO3 adsorbed to an O(2-) site forms a trigonal pyramidal SO4 species which yields, with a low barrier, a tetrahedral sulfate anion. Subsequently the anion reorients on the surface. Alternative mechanisms which require the formation of Ni(3+) or O(-) are discussed. NiSO4 thus formed may play a passivating role for the corrosion of Ni at low temperatures in the SO2 + O2 + SO3 atmospheres and an active role at high temperatures, as discussed in the experimental literature.

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

1986-01-01

378

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

EPA Science Inventory

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

379

Laboratory-Measured Sulfuric Acid and Water Homogeneous Nucleation Rates from the SO2 + OH Reaction  

Microsoft Academic Search

Sulfuric acid and water binary homogeneous nucleation is the most important atmospheric nucleation system, but the nucleation mechanisms are poorly understood. Here, we report laboratory-measured sulfuric acid and water binary homogeneous nucleation rates at the atmospheric pressure, 288 K and 10 - 55 % relative humidity. The SO2 + OH reaction was used to produce sulfuric acid vapor. Residual sulfuric

D. Benson; S. Lee

2007-01-01

380

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

381

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...

382

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...

383

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 ...

384

Complexation of n SO2 molecules (n = 1, 2, 3) with formaldehyde and thioformaldehyde  

NASA Astrophysics Data System (ADS)

Ab initio and density functional theory calculations are used to examine complexes formed between H2CO and H2CS with 1, 2, and 3 molecules of SO2. The nature of the interactions is probed by a variety of means, including electrostatic potentials, natural bond orbital, atoms in molecules, energy decomposition, and electron density redistribution maps. The dimers are relatively strongly bound, with interaction energies exceeding 5 kcal/mol. The structures are cyclic, containing both a O/S⋯S chalcogen bond and a CH⋯O H-bond. Addition of a second SO2 molecule leads to a variety of heterotrimer structures, most of which resemble the original dimer, where the second SO2 molecule engages in a chalcogen bond with the first SO2, and a C⋯O attraction with the H2CX. Some cooperativity is apparent in the trimers and tetramers, with an attractive three-body interaction energy and shortened intermolecular distances.

Azofra, Luis Miguel; Scheiner, Steve

2014-01-01

385

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

386

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...

387

STUDY OF AUTOMATIC CONTROL SYSTEM TO MAINTAIN CONSTANT PERCENTAGE SO2 RETENTION IN A PRESSURIZED FBC  

EPA Science Inventory

The report gives results of an assessment of the feasibility of using automatic controls to maintain a constant percentage SO2 removal in a pressurized fluidized-bed boiler (PFB) system as variations occur; e.g., in coal sulfur content or sorbent reactivity. The Clean Air Act ame...

388

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

EPA Science Inventory

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

389

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...

390

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...

391

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 ...

392

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

E-print Network

93- 79.01 1 Performance Model of the Fluidized Bed Copper Oxide Process for SO2/NOx Control H H.C. Frey #12;93- 79.01 2 INTRODUCTION The fluidized bed copper oxide process is an advanced design issues, including overall sulfur removal efficiency, fluidized bed absorber height, sorbent copper

Frey, H. Christopher

393

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...

394

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

EPA Science Inventory

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

395

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...

396

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

E-print Network

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

Dickerson, Russell R.

397

Sulfur Dioxide (SO2) Primary NAAQS Review: Integrated Review Plan - Advisory with CASAC  

EPA Science Inventory

The SO2 Integrated Review Plan is the first document generated as part of the National Ambient Air Quality Standards (NAAQS) review process. The Plan presents background information, the schedule for the review, the process to be used in conducting the review, and the key policy-...

398

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

399

Low to negligible BrO/SO2 ratios at two subduction-zone volcanoes  

NASA Astrophysics Data System (ADS)

In July 2013 a measurement campaign took place on Kyushu, Japan, investigating the BrO/SO2 ratio in the plume of Sakurajima and Aso. Multi-Axis-Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were carried out at four sides on Sakurajima Island, with a maximum distance of about 5 km downwind, and assuming a wind speed of 5 m/s (corresponding to a plume age of about 15 minutes). At Aso measurements took place on the western slope of the active crater and at the crater rim. The MAX-DOAS data of both sites were evaluated for BrO and SO2 slant column densities (SCDs). In the following, BrO/SO2 ratios were calculated to overcome dilution effects and to investigate the BrO formation processes in the ash-laden plume of Sakurajima and the volcanic plume of Aso which is characterized by emissions from a fumarolic area and a mud pool. The BrO/SO2 ratios of the measurement have been below the detection limit for Aso as well as during most of the measurement days at Sakurajima with the only exception on 15th July 2013, when a BrO/SO2 ratio of ~ 1 x 10-5 could be determined. After very high BrO/SO2 ratios at Sakurajima that were reported by C. Lee et al. (2005) our results seem to be unexpected but nevertheless match the general geological settings at both volcanoes. In a recent paper, Shinohara (2013) summarized and compared chlorine emissions from the Japanese volcanic arc with global chlorine emissions from arc volcanoes and pointed out that the volcanic gas emissions in Japan are quite Cl-poor compared to those at other subduction zones. In the recent past it has been found that low chlorine emissions can occur together with nevertheless high bromine emissions (Nyiragongo, Bobrowski et al., 2013). However, looking up Br/Cl ratios (of condensate measurements at fumaroles) of the Japanese arc volcanism summarized in Gerlach, 2004 a comparatively low Br/Cl ratio is added with 6-7 x 10-4 (global arc mean 2 x 10-3) to the already poor chlorine emissions. We will present upper limits of BrO/SO2 ratios and give an estimate on bromine emissions of Aso and Sakurajima for July 2013. To our knowledge these are the so far lowest bromine emission from an arc volcano. Possible reasons will be discussed in the light of today's available literature - pointing out the geological particularities on Eurasian-Philippine plate subduction zone.

Bobrowski, Nicole; Hörmann, Christoph; Mori, Toshiya; Platt, Ulrich

2014-05-01

400

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

401

Hydrogen Peroxide Enhances Removal of NOx from Flue Gases  

NASA Technical Reports Server (NTRS)

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

Collins, Michelle M.

2005-01-01

402

Regional climate responses to geoengineering with tropical and Arctic SO2 injections  

NASA Astrophysics Data System (ADS)

Anthropogenic stratospheric aerosol production, so as to reduce solar insolation and cool Earth, has been suggested as an emergency response to geoengineer the planet in response to global warming. While volcanic eruptions have been suggested as innocuous examples of stratospheric aerosols cooling the planet, the volcano analog actually argues against geoengineering because of ozone depletion and regional hydrologic and temperature responses. To further investigate the climate response, here we simulate the climate response to both tropical and Arctic stratospheric injection of sulfate aerosol precursors using a comprehensive atmosphere-ocean general circulation model, the National Aeronautics and Space Administration Goddard Institute for Space Studies ModelE. We inject SO2 and the model converts it to sulfate aerosols, transports the aerosols and removes them through dry and wet deposition, and calculates the climate response to the radiative forcing from the aerosols. We conduct simulations of future climate with the Intergovernmental Panel on Climate Change A1B business-as-usual scenario both with and without geoengineering and compare the results. We find that if there were a way to continuously inject SO2 into the lower stratosphere, it would produce global cooling. Tropical SO2 injection would produce sustained cooling over most of the world, with more cooling over continents. Arctic SO2 injection would not just cool the Arctic. Both tropical and Arctic SO2 injection would disrupt the Asian and African summer monsoons, reducing precipitation to the food supply for billions of people. These regional climate anomalies are but one of many reasons that argue against the implementation of this kind of geoengineering.

Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.

2008-08-01

403

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

404

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

405

Discovery of the SO_2 7.3 microns Band in Oxygen-rich Miras  

NASA Astrophysics Data System (ADS)

We have detected the nu_3 = 0-1 ro-vibrational band of SO_2 for the first time in the spectra of three oxygen-rich Miras, obtained by the Short-Wavelength Spectrometer on board the Infrared Space Observatory. The band at 7.3 microns is seen as a deep absorption in UX Cyg, while it is in emission in o Cet. Seven spectra of T Cep taken at different phases show that the feature changed from emission to absorption on a time scale of about one year. The band may be marginally seen in most of other stars in our sample of about 10 O-rich long-period variables. Using a simple plane-parallel model with a uniform excitation temperature, we derive the physical conditions in the SO_2 molecular layer. It is found that all observations are fitted fairly well with a single excitation temperature of 600 K, and that the molecule is extended over several stellar radii. The result is comparable to that obtained from the CO_2 ro-vibrational bands in the 12 - 16 microns region (Cami et al. this conference), suggesting that SO_2 and CO_2 are located in the same layer just below the dust forming region. The total number of molecules in the region is of the order of 1047. To contain this amount of molecules in a region of a few stellar radii, the local density must be as high as 1010 hydrogen atoms per cm^3, more than two orders of magnitude larger than expected from model atmosphere calculations. This conclusion is consistent with the CO_2 analysis. The variability of the T Cep spectra may be explained by the dissociation of SO_2 molecules in the outer parts of the region resulting in the shrinking of the SO_2 layer. However, it is difficult to understand the observed high abundance of SO_2 based on presently known chemical formation and destruction processes. This work is based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA. The SWS is a joint project of SRON and MPE.

de Jong, T.; Yamamura, I.; Cami, J.; Onaka, T.; Waters, L. B. F. M.

406