Atmospheric Sulfur Dioxide Research Articles

Long-Term and Mobile Monitoring of Atmospheric Sulfur Dioxide and Hydrogen Sulfide at Mt. Aso and Kumamoto City

フロー分析の大気成分測定への応用について，長期にわたる連続分析を通しその実用性や信頼性に関する評価検討を行った．分析システムは，多孔性メンブランチューブから成る拡散スクラバーにガス捕集反応溶液を連続的に通じ，下流の検出器で大気中の二酸化硫黄及び硫化水素を同時測定するものである．本分析システムを阿蘇山と熊本市の2箇所に設置し，2年半にわたって分析を続けた．熊本市では，SO2とH2Sの日変化は逆転する傾向があった．これに対し，阿蘇でのガス濃度は火山活動の影響を強く受け，活動の活発な時期にSO2濃度が高くなるとともにSO2/H2S濃度比も大きく上昇した．更に本システムをポータブル分析計として活用し，阿蘇火口周囲での測定を5回にわたり行い，ガスの分布や存在比に関する知見を得た．また，火口壁近傍では，3～4けたのガス濃度変化が短い時間で起こっていることも観測された．

Micro gas analysis system for measurement of atmospheric hydrogen sulfide and sulfur dioxide

A honeycomb structure microchannel scrubber was developed to achieve efficient and stable gas collection. A thin porous membrane was pasted on a microchannel by the adhesive force of a fresh polydimethylsiloxane surface. The microchannel scrubber achieved much more efficient gas collection than conventional impingers and diffusion scrubbers. Two sets of the microchannel scrubbers and detectors were integrated in a 10 cm x 9 cm plastic board to create a micro gas analysis system (microGAS) for simultaneous measurements of H2S and SO2. The whole system including a battery was incorporated in a carrying case 34 cm W x 16 cm D x 17 cm H for use in the field. Liquid flows at 30 microl min(-1) were obtained by bimetal micropumps. The estimated detection limits were 0.1 ppbv for H2S and 1 ppbv for SO2. The system was demonstrated for real atmospheric gas analysis, and the results agreed well with data concurrently obtained by ion chromatography coupled with a cylindrical diffusion scrubber. The system we developed allowed automated continuous analyses in the field and achieved a much higher time resolution compared to those by ion chromatographic analysis.

Satellite observations of atmospheric SO 2 from volcanic eruptions during the time-period of 1996–2002

In this article, we present satellite observations of atmospheric sulfur dioxide (SO 2) from volcanic eruptions. Global ozone monitoring experiment (GOME) data for the years 1996–2002 is analyzed using a DOAS based algorithm with the aim of retrieving SO 2 slant column densities (SCD). The retrieval of SO 2 SCD in the UV spectral region is difficult due to strong and interfering ozone absorptions. It is also likely affected by instrumental effects. We investigated these effects in detail to obviate systematic biases in the SO 2 retrieval. A quantitative study of about 20 volcanoes from Italy, Iceland, Congo/Zaire, Ecuador, Japan, Vanuatu Island and Mexico is presented. The focus is on both eruption and out gassing scenarios. We prepared a 7-year mean map (1996–2002) of SO 2 SCD observed by GOME and tabulated the ratios of the maximum SO 2 SCD observed to the average SO 2 SCD as seen in the 7-year mean map. The further aim of this study is to provide information about unknown volcanic eruptions, e.g., Bandai Honshu Japan, Central Islands Vanuatu, Piton de la Fournaise Réunion Island France, Kamchatka region of Russia and from Indonesia especially. The results demonstrate a high sensitivity of the GOME instrument towards SO 2 emissions during both eruption and degassing episodes.

Sulphur Deficiency Causes a Reduction in Antimicrobial Potential and Leads to Increased Disease Susceptibility of Oilseed Rape

AbstractThe reduction of atmospheric sulphur dioxide pollution is causing increasing problems of sulphur deficiency in sulphur‐demanding crop plants in northern Europe. Elemental sulphur and many sulphur containing compounds such as cysteine‐rich antifungal proteins, glucosinolates (GSL) and phytoalexins play important roles in plant disease resistance. The aim of this work was to analyse the effect of inadequate sulphur supply on disease resistance of oilseed rape (Brassica napus). Compared with fertilized oilseed rape, healthy looking S‐deficient plants showed increased susceptibility to the blackleg fungus Leptosphaeria maculans, to the generalist necrotroph Botrytis cinerea and to the oomycete Phytophthora brassicae. To analyse possible causes of the increased disease susceptibility of S‐deficient plants, protein extracts and methanolic extracts of secondary metabolites of plants grown with and without adequate sulphur supply were tested for antimicrobial activity. None of the protein extracts showed antimicrobial activity. However, extracts containing secondary metabolites from normally grown plants showed a strong antimicrobial activity in in vitro tests with various fungal and bacterial pathogens. This activity was almost totally lost in extracts derived from S‐deficient plants. The antimicrobial activity did not appear to be based on the activity of phytoalexins because it was present in healthy plants and was not increased by a previous inoculation with Botrytis cinerea. The loss of antifungal activity in S‐deficient plants correlated with a strong reduction of various GSL, thus suggesting a reduced level of GSL as a possible cause of the reduced antimicrobial potential. However, limited tests of commercially available GSL or their degradation products did not demonstrate a causal link. Our results show that S‐deficiency of oilseed rape negatively affects disease resistance and suggest that this effect is at least partially caused by a reduction of sulphur‐dependent phytoanticipins.

Air pollution: A half century of progress

AbstractIn the 50 years since the air pollution episodes of Donora, PA and London, U.K., a great deal of progress has been made in understanding the nature and sources of air pollution and the atmospheric transport and transformation of pollutants. Also, many significant technological advances in air pollution control equipment, such as the automobile exhaust gas catalytic converter, have led to effective reduction of emissions from a variety of major pollution sources. Finally, remarkable developments in instrumentation for sampling the trace species in the atmosphere have been and continue to be made. Relatively less progress has been made in understanding the biological mechanisms by which pollutants lead to human injury and mortality. In this review the focus is on the extraordinary progress that has been made over the last half century in understanding the atmospheric nature and behavior of pollutants, both gaseous and particulate. A major breakthrough was the determination of the gas‐phase chemistry of both the natural and polluted atmosphere, chemistry that leads to the formation of ozone and a vast array of oxidized molecules. The mechanisms of the oxidation of atmospheric sulfur dioxide, one of the main primary pollutants, were elucidated. Finally, the chemistry, physics, and optics of atmospheric particulate matter (aerosols) have been laid open by many stunning research achievements. Whereas 50 years ago air pollution was thought to be confined to the area around a city, it is now recognized that species emitted on one continent frequently find their way to other continents. Strategies for dealing with a truly global atmospheric backyard now represent a major challenge. © 2004 American Institute of Chemical Engineers AIChE J, 50:1096–1108, 2004

Utilizing stable isotope abundances of lichens to monitor environmental change

Reported field observations, laboratory studies and transplant experiments confirm that lichens are affected by pollutants. The ubiquitous nature of lichens and their susceptibility to the environment suggest that their response to variations in atmospheric composition might provide a useful means for monitoring environmental quality. Through such monitoring, the detection of abnormal levels of defined pollutants in the atmosphere would be an indicator of the need for remedial action before dramatic evidence of environmental damage becomes apparent. An additional advantage would be that previously unrecognized pollution sources affecting lichens and the wider environment might be detected. As lichens have important ecological and economic roles in our society, recognition of lichen communities at risk would be an associated benefit.The stable isotope abundance of carbon in the lichen Cladia aggregata has been investigated in a study relating these values with known levels of selected pollutants in the region within a 200-km radius of Sydney, Australia. A total of 129 samples of the sterile and fertile forms of the lichen was obtained from 36 different sites. There was an 8‰ range in the δ13C values of these samples of whole lichen. Small effects on δ13C values in the lichen, of less than ±1‰, were found to be associated with distance from pollution source, slope of the substrate site, humidity, altitude and number of rain days at the sampling site. The effects of the natural parameters tend to cancel out. A statistically significant negative correlation between δ13C values in the whole lichen and atmospheric sulphur dioxide concentrations was found. This is consistent with the known destructive effect of SO2 on lichens. δ13C values in lichens in wet environments, in the presence of high SO2 concentrations, were more negative than in samples from drier sites. The direction of this relationship is contrary to that observed in laboratory studies by other workers. An explanation of this effect may relate to an increase in carboxylation resistance resulting from damage to chlorophyll and cell structure by SO2, which over-rides an inverse effect of CO2 resistance that increases with wetting of the lichens. The predictive reliability of the graphical tool formulated from these data requires the accumulation of data for atmospheric SO2 concentrations localized to sampling sites, followed by further testing.

Effects of simultaneous exposure to atmospheric sulfur dioxide and heavy metals on the yield and metal content of soybean grain (Glycine max [L.] Merr.).

Effects of simultaneous exposure to atmospheric sulfur dioxide and heavy metals on the yield and metal content of soybean grain (Glycine max [L.] Merr.).

Size distribution of acidic sulfate ions in fine ambient particulate matter and assessment of source region effect

Human exposure studies strongly suggested that the fine fraction of ambient particulate matter (PM) and its associated acidic sulfates are closely correlated with observed adverse health effects. Acidic sulfates are the products of atmospheric sulfur dioxide oxidation and neutralization processes. Few data are available on the amount and size distribution of acidic sulfates within the fine fraction of ambient PM. Knowledge of this distribution will help to understand their toxic mechanisms in the human respiratory tract. The goals of this research were: (1) to measure the size distribution of hydrogen ion, sulfate, and ammonium within the fine fraction of the ambient aerosol in air masses originating from different source regions; and (2) to examine the effect of the source region and the seasons on the sampled PM composition. Six size fractions within the fine ambient PM were collected using a micro-orifice impactor. Results from 30 sampling sessions demonstrated that higher total concentrations of these three ions were observed during the warm months than during the cold months of the year. Size distribution results show that the midpoint diameter of the fraction of particles with the largest fraction of hydrogen, sulfate and ammonium ions was 0.38 μm. Although most of the mass containing hydrogen and sulfate ions was measured in the fraction of particles with 0.38 μm midpoint diameter, the ultrafine fraction (<0.1 μm) was found to be more acidic. Ambient ion concentrations varied between sampling sessions and seasons, but the overall size distribution profiles are similar. Air mass back trajectories were used to identify the source region of the sampled aerosols. No apparent source region effect was observed in terms of the distribution profile of the ions. However, samples collected from air masses that originated from, or passed over, high sulfur dioxide emission areas demonstrated higher concentrations of the different ions.

“Clear skies” Proposal draws mixed reactions at Senate Hearing

The Bush administration's “Clear Skies Initiative” proposal to reduce atmospheric sulfur dioxide, nitrogen oxides, and mercury was described at an 8 April Senate hearing as a good amendment to the Clean Air Act, and alternately, as a delay in attaining a cleaner environment.The hearing, by the Senate Environment and Public Works Subcommittee on Clean Air, Climate Change, and Nuclear Safety, was the first of several anticipated this session on the Clear Skies Act (S.485), which represents the administration's top environmental initiative.

Sources of atmospheric acidity in an agricultural‐industrial region of São Paulo State, Brazil

Surface‐based measurements of atmospheric formic acid (HCOOH), acetic acid (CH3COOH), sulfur dioxide (SO2), hydrogen chloride (HCl), and nitric acid (HNO3) were made in central São Paulo State, Brazil, between April 1999 and March 2000. Mean concentrations were 9.0 ppb (HCOOH), 1.3 ppb (CH3COOH), 4.9 ppb (SO2), 0.3 ppb (HCl), and 0.5 ppb (HNO3). Concentrations in sugar cane burning plumes were 1160–4230 ppb (HCOOH), 360–1750 ppb (CH3COOH), 10–630 ppb (SO2), 4–210 ppb (HCl), and 14–90 ppb (HNO3). Higher ambient concentrations of SO2, HCl and HNO3 were measured during the burning season (May–November). Concentrations of SO2 and HCl increased during the evening, and of HCOOH and CH3COOH were lowest in the morning, with peak levels in the afternoon. Ratios obtained between different species showed either nighttime maxima (SO2/HCOOH, SO2/CH3COOH, SO2/HNO3, CH3COOH/HNO3, SO2/HCl and HCOOH/HNO3), daytime maxima (HCOOH/HCl, CH3COOH/HCl and HNO3/HCl), or no clear trends (HCOOH/CH3COOH). Correlation analysis showed that SO2 and HCl were primary emissions from biomass burning and road transport; HCOOH, HNO3 and CH3COOH were products of photochemistry; HCOOH and CH3COOH were emitted directly during combustion as well as from biogenic sources. Biomass burning affected atmospheric acidity on a regional scale, while vehicular emissions had greater impact in urban and adjacent areas. Atmospheric ammonia levels were insufficient to neutralize atmospheric acidity, which was mainly removed by deposition to the surface.

Continuous Monitoring of Sulfur Dioxide with a Gas Permeation Denuder-Based System

This study describes a continuous flow pro- cedure for monitoring atmospheric sulfur dioxide using a planar gas permeation denuder (GPD) and a fiber optic spectrometer. When gaseous samples are directed through a GPD which consists of a gas-perme- able membrane of poly(vinylidene) difluoride and two perspex blocks with engraved channels of mirror image, the fraction of sulfur dioxide passing the membrane is absorbed in a flowing stream of 5.0� 10 � 4 mol L � 1 5,5 0 -dithiobis(2,2 0 -dinitrobenzoic acid) (DTNB) in 0.025 mol L � 1 phosphate buffer of pH 7.0, and reacts with DTNB to yield a yellow product. This product is monitored spectrophotometrically at 410 nm with a miniature charge-coupled device (CCD) fiber optic spectrometer. The analytical range of sulfur diox- ide is easily adjusted via the flow rate of DTNB solu- tion, normally from 200 ppb to 94 ppm (v=v). The procedure is hardly interfered with by coexisting metal and non-metal species, except for hydrogen sulfide in the atmosphere. The error caused by hydrogen sulfide at a sulfur dioxide level (in ppm) of 2% is less than � 10%. With the proposed procedure, the result for a mimetic air sample is very close to that of the ultra- violet fluorescence method.

Construction and performance of a drop cell for the nephelometric determination of sulfur dioxide

A nephelometric technique based on a liquid drop is described for the measurement of atmospheric sulfur dioxide. A 40-μl drop of barium chloride and hydrogen peroxide solution is suspended in a flowing-air sampling stream. The sulfur (IV) collected is oxidized to sulfur (VI) and finally precipitated as barium sulfate. Nephelometric detection of drop is achieved by an appropriate arrangement consisting of an optical fiber contacting the drop and a photodiode placed at 90° relative to the fiber. The design and characteristics of this drop-based gas sensor system are described. The analytical response, as photocurrent, is proportional to the product of the sampling period and the sulfur dioxide concentration. The detection limit is ca. 1.1 mg m −3 for a 10-min sampling time. The present technique is fairly rapid and simple, uses a small amount of reagent and is set up with low-cost equipment, making this system economically viable.

Spatial Distribution and Yearly Variation of Atmospheric Sulfur Dioxide Concentration in China during 1990's (19911999)

Spatial Distribution and Yearly Variation of Atmospheric Sulfur Dioxide Concentration in China during 1990's (19911999)

Hybrid microfabricated device for field measurement of atmospheric sulfur dioxide.

A miniaturized planar-membrane-based gas collector of 800 nL internal liquid volume was integrated with a microfabricated conductivity detector to measure atmospheric SO2. This device is operated with a dilute H2SO4/ H202/2-propanol absorber for a finite integration period (typically, 1.5 min) without liquid flow. During this period, sulfuric acid is formed from SO2 that diffuses into the liquid and accumulates therein. The increase in conductivity with ongoing sampling is measured. The absorber is then replaced with fresh solution, and the process starts anew. The most important factors that govern sensitivity and the detection limit are the choice of the membrane, the nature of the internal collector solution, and the thickness of the solution layer. A porous polypropylene membrane with some 2-propanol (IPA) incorporated in the internal solution was found to be the best combination. The sensitivity was inversely proportional to the solution layer thickness, and a layer thickness of 100 microm resulted in a practical device with good performance characteristics. Greater applied pressure on the gas phase relative to the liquid side also can improve device performance. The system is operated with 12 V DC and does not require a liquid pump. Under optimized conditions, the LOD is 0.7-1.0 ppbv for a sampling period of 1.5 min. The device was field-tested around Mt. Aso in Japan. Changes in ambient SO2 concentrations could be followed with good time resolution. The results are compared with data obtained by a collocated macroscale instrument.

Wavelength dependence of aerosol optical thickness in the UV‐B band

The optical thickness of the atmosphere, τat, was deduced from measurements of narrowband direct solar UV‐B (280–320 nm) radiation. This is the radiation that is strongly absorbed in the stratosphere by ozone, especially near the lower limit wavelength of these measurements, 306.3 nm. Measurement campaigns were organized to obtain radiation data at different sites, for different kinds of aerosol, using the same methods and instruments, in order to deduce the atmospheric optical thickness for different atmospheric conditions. The measurements were made with a Brewer spectrophotometer at each site. This instrument measures also the atmospheric ozone and sulphur dioxide columns, and therefore it is possible to deduce the aerosol optical thickness, τae. The possibility of additional absorptions in the UV‐B band, especially formaldehydes, is investigated. Two data sets are examined: C. Grande and S. Paulo. A large percentage of the data show that the wavelength dependence of the aerosol optical thickness is one that appears to increase with wavelength. In other words, the difference between the absolute values at 320.1 and 306.3 nm, is positive for the majority of cases. However, this difference is not always larger than the uncertainty/error of the measurement. This intriguing result opposes the Angstrom law, applicable to a much larger dynamic range in wavelength. For the C. Grande data (with generally larger values of optical thickness), the difference is positive in 16 out of 19 cases, but there are only 4 cases when the difference is larger than the error. For the S. Paulo morning data, however, the opposite is true. The difference is positive with only one exception, and there are 13 cases out of 17 where the difference is larger than the error.

DMS and SO2 at Baring Head, New Zealand: Implications for the Yield of SO2 from DMS

Atmospheric dimethyl sulfide (DMS) and sulfur dioxide (SO2) concentrations were measured at Baring Head, New Zealandduring February and March 2000. Anti-correlated DMS and SO2 diurnalcycles, consistent with the photochemical production of SO2 from DMS, were observed in clean southerly air off the ocean. The data is used to infer a yield of SO2 from DMS oxidation. The estimated yields are highly dependent on assumptions about the DMS oxidation rate. Fitting the measured data in a photochemical box model using model-generated OH levels and the Hynes et al. (1986) DMS + OH rate constant suggests that theSO2 yield is 50–100%, similar to current estimates for the tropical Pacific.However, the observed amplitude of the DMS diurnal cycle suggests that the oxidation rate is higher than that used by the model, and therefore, that theSO2 yield is lower in the range of 20–40%.

Sulfur isotopic compositions and source identification of atmospheric sulfur dioxide, sulfate in aerosols and in bulk precipitation collected over Kyushu Island, Japan

Sulfur isotopic compositions and source identification of atmospheric sulfur dioxide, sulfate in aerosols and in bulk precipitation collected over Kyushu Island, Japan

Fast airborne sulfur dioxide measurements by Atmospheric Pressure Ionization Mass Spectrometry (APIMS)

[i] An atmospheric pressure ionization mass spectrometer (APIMS) was developed to determine atmospheric sulfur dioxide (SO 2 ). High precision and immunity to sample loss, fluctuations in instrument sensitivity, etc., were achieved by adding isotopically labeled SO 2 ( 34 S 16 O 2 ) continuously to the manifold as an internal standard. During the NASA Transport And Chemical Evolution Over The Pacific (TRACE P) program and the National Science Foundation (NSF) Passing Efficiency of the Low Turbulence Inlet (PELTI) program, 32 S 16 O 2 and 34 S 16 O 2 were each determined with integration times of 20 ms. From these data the ambient SO 2 level was computed every 40 ms. In the PELTI studies at SO 2 levels of approximately 60 parts per trillion by volume (pptv), vertical fluxes were determined with a precision better than 10%. When the data were averaged to 1 s, the lower limit of detection was <1 pptv at the 2a level. Isotopomer ratios observed during the Aerosol Characterization Experiment-Asia (ACE Asia), intercomparisons of APIMS and gas chromatography/mass spectrometry with isotopically labeled internal standard on the same aircraft in test flights and PELTI, and the intercomparison of two APIMS instruments on different aircraft during ACE Asia and TRACE P, are presented to support the high sensitivity, accuracy, specificity, and high time response of the instrument.

The Recent Evolution of Climate on Venus

The present climate of Venus is controlled by an efficient carbon dioxide–water greenhouse effect and by the radiative properties of its global cloud cover. Both the greenhouse effect and clouds are sensitive to perturbations in the abundance of atmospheric water vapor and sulfur gases. Planetary-scale processes involving the release, transport, and sequestering of volatiles affect these abundances over time, driving changes in climate. We have developed a numerical model of the climate evolution of Venus. Atmospheric temperatures are calculated using a one-dimensional two-stream radiative–convective model that treats the transport of thermal infrared radiation in the atmosphere and clouds. These radiative transfer calculations are the first to utilize high-temperature, high-resolution spectral databases for the calculation of infrared absorption and scattering in Venus' atmosphere. We use a chemical/microphysical model of Venus' clouds to calculate changes in cloud structure that result from variations in atmospheric water and sulfur dioxide. Atmospheric abundances of water, sulfur dioxide, and carbon dioxide change under the influence of the exospheric escape of hydrogen, outgassing from the interior, and heterogeneous reactions with surface minerals. Radar images from the Magellan mission show that the surface of Venus has been geologically active on a global scale, yet its sparse impact cratering record is almost pristine. This geologic record on Venus is consistent with an epoch of rapid plains emplacement 600–1100 Myr ago. Our models show that intense volcanic outgassing of sulfur dioxide and water during this time would have resulted in the formation of massive sulfuric acid/water clouds and the cooling of the surface for 100–300 Myr. The thick clouds would have subsequently given way to high, thin water clouds as atmospheric sulfur dioxide was lost to reactions with the surface. Surface temperatures approaching 900 K would have been reached 200–500 Myr after the onset of volcanic resurfacing. Evolution to current conditions would have proceeded due to loss of atmospheric water at the top of the atmosphere, ongoing low-level volcanism, and the reappearance of sulfuric acid/water clouds. We find that the maintenance of sulfuric acid/water clouds on Venus today requires sources of outgassed sulfur active in the past 20–50 Myr, in contrast with the 1.9 Myr as determined from geochemical arguments alone (B. Fegley and R. G. Prinn 1989, Nature 337, 55–58).

Daytime atmospheric sulphur dioxide concentrations in Ibadan city, Nigeria

Atmospheric sulphur dioxide concentrations were determined at 27 locations in the city of Ibadan, Nigeria, during May-June 1997. The locations were chosen from zones of high and low traffic densities, residential areas, industrial areas, and remote (control) areas. Sulphur dioxide levels did not significantly vary with the time of day of sampling, which was between 9 a.m. and 5 p.m. Average levels were: high and medium traffic density zones, 34.8 mg/m3; low traffic density and residential zones, 20.0 mg/m3; industrial zones, 68.9 mg/m3; and control zones, 14.5 mg/m3. The average level for all the zones, 34.1 mg/m3, is within the limits of worldwide guidelines for air quality, but slightly higher than prevailing levels in some cities of the developed countries. (Received January 5, 2001; revised July 10, 2001)(Bulletin of The Chemical Society of Ethiopia: 2003 15 (1): 71-78)