SO Transformations Research Articles

Describing metric-affine theories anew: alternative frameworks, examples and solutions

In this work we describe metric-affine theories anew by making a change of field variables. A series of equivalent frameworks is presented and identifications are worked out in detail. The advantage of applying the new frameworks is that any MAG theory can be handled as a Riemannian theory with additional fields. We study the Hilbert-Palatini action using the new field variables and disclose interesting symmetries under SO transformations in field space. Then, we use solvable and suitable Riemannian theories as seed models for solvable MAG theories, restricting ourselves to three examples. We present a black hole solution with torsion and non-metricity which under a certain tuning acquires a regular core. A de Sitter universe with the expansion powered by 3-form torsion, is also reported.

Modeling of aerosol property evolution during winter haze episodes over a megacity cluster in northern China: roles of regional transport and heterogeneous reactions of SO<sub>2</sub>

Abstract. Regional transport and heterogeneous reactions have been shown to play crucial roles in haze formation over a megacity cluster centered on Beijing. In this study, the updated Nested Air Quality Prediction Model System (NAQPMS) and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model were employed to investigate the evolution of aerosols – in terms of the number concentration, size distribution, and degree of aging – in Beijing during six haze episodes between 15 November and 15 December 2016, as part of the Air Pollution and Human Health–Beijing (APHH-Beijing) winter campaign of 2016. The model exhibited reasonable performance not only with respect to mass concentrations of PM2.5 and its components in Beijing but also regarding the number concentration, size distribution, and degree of aging. We revealed that regional transport played a non-negligible role in haze episodes, with contributions of 14 %–31 % to the surface PM2.5 mass concentration. The contribution of regional transport to secondary inorganic aerosols was larger than that to primary aerosols (30 %–63 % and 3 %–12 %, respectively). The chemical transformation of SO2 along the transport pathway from source regions to Beijing was the major source of SO42-. We also found that sulfate formed outside Beijing from SO2 emitted in Beijing; this sulfate was then blown back to Beijing and considerably influenced haze formation. Along the transport pathway, aerosols underwent aging, which altered the mass ratio of the coating of black carbon to black carbon (RBC) and the size distribution of number concentrations. During the episodes, the geometric mean diameter (GMD) increased from less than 100 nm at the initial site to approximately 120 nm at the final site (Beijing), and the RBC increased from 2–4 to 4–8. During haze episodes with high humidity, the average contributions of gas and aqueous chemistry, heterogeneous chemistry, and primary emission to sulfate were comparable. However, their relative contributions varied with pollution levels. Primary emissions had the greatest impact under light to moderate pollution levels, whereas heterogeneous chemistry had a stronger effect under high pollution levels.

Unilateral follicular variant of papillary thyroid carcinoma with unique KRAS mutation in struma ovarii in bilateral ovarian teratoma: a rare case report

BackgroundStruma ovarii (SO) is a rare form of ovarian mature teratoma in which thyroid tissue is the predominant element. Because of its rarity, the differential diagnosis between benign and malignant SO has not been clearly defined. It is believed that malignant transformation of SO has similar molecular features with and its prognosis corresponds to that of malignant tumors originating in the thyroid.Case presentationWe report 35-year-old woman with bilateral ovarian cysts incidentally detected by ultrasound during the first trimester of pregnancy. Four months after delivery of a healthy child without complication she was admitted to the hospital for acute abdominal pain. Laparoscopic left adnexectomy was performed initially in a regional hospital; right cystectomy was done later in a specialized clinic. Intraoperative frozen section and a final pathology revealed that the cyst from the left ovary was composed of mature teratomatous elements, normal thyroid tissue (>50%) and a non-encapsulated focus of follicular variant of papillary thyroid carcinoma (PTC).Normal and cancerous thyroid tissues were tested for BRAF and RAS mutations by direct sequencing, and for RET/PTC rearrangements by RT-PCR/Southern blotting. A KRAS codon 12 mutation, the GGT → GTT transversion, corresponding to the Gly → Val amino acid change was identified in the absence of other genetic alterations commonly found in PTC.ConclusionTo the best of our knowledge, this is the first time this mutation is described in a papillary thyroid carcinoma arising in struma in the ovarii. This finding provides further evidence that even rare mutations specific for PTC may occur in such tumors. Molecular testing may be a useful adjunct to common differential diagnostic methods of thyroid malignancy in SO.

On AGT description of $ \mathcal{N} = 2 $ SCFT with N f = 4

We consider Alday-Gaiotto-Tachikawa (AGT) realization of the Nekrasov partition function of $ \mathcal{N} = 2 $ SCFT. We focus our attention on the SU(2) theory with N f = 4 flavor symmetry, whose partition function, according to AGT, is given by the Liouville four-point function on the sphere. The gauge theory with N f = 4 is known to exhibit SO(8) symmetry. We explain how the Weyl symmetry transformations of SO(8) flavor symmetry are realized in the Liouville theory picture. This is associated to functional properties of the Liouville four-point function that are a priori unexpected. In turn, this can be thought of as a non-trivial consistency check of AGT conjecture. We also make some comments on elementary surface operators and WZW theory.

High‐purity nano particles ZnS production by a simple coupling reaction process of biological reduction and chemical precipitation mediated with EDTA

High-purity nanoparticles ZnS has been successfully synthesized using a simple coupling reaction process of biological reduction and chemical precipitation mediated with EDTA referred to as the CRBRCP-EDTA process. This research investigated the optimum conditions of the transformation of SO(4) (2-) into S(2-) by SRB, and the production of ZnS in the CRBRCP-EDTA process. The results showed that the molar ratio of Zn(2+) to EDTA = 1:1 was crucial for SRB growth and ZnS synthesis. At the ratio(n) (Zn2+)/n) (EDTA) = 1:1, lower Zn(2+) concentration enhanced both the growth of SRB and the reduction of SO(4) (2-), leading to higher ZnS production. Although increase in Na(2)SO(4) concentration resulted in decrease in both SRB growth and SO(4) (2-) reduction, it improved the S(2-) and ZnS production. Under the optimum conditions (0.05 mol L(-1) ZnCl(2), 0.05 mol L(-1) EDTA, and 0.1 mol L(-1) Na(2)SO(4)), the synthesized ZnS was characterized by X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The analysis showed that the obtained ZnS were high-purity and well-distributed solid spheres with diameters of about 15 nm for primary particles and around 400 nm for secondary particles. When polyacrylamide (PAM) was incorporated in the CRBRCP-EDTA process, the secondary particle's diameters were reduced to less than 100 nm. The photoluminescence (PL) spectra of produced ZnS centered at 396 nm, the spectrum with PAM added showed the gradual increase in absorption and stronger intensity in PL property. The present simple, low-cost, and safe method may be extended to prepare other metal-sulfide nanocomposites.

The air pollution caused by the burning of fireworks during the lantern festival in Beijing

The effects of the burning of fireworks on air quality in Beijing was firstly assessed from the ambient concentrations of various air pollutants (SO 2, NO 2, PM 2.5, PM 10 and chemical components in the particles) during the lantern festival in 2006. Eighteen ions, 20 elements, and black carbon were measured in PM 2.5 and PM 10, and the levels of organic carbon could be well estimated from the concentrations of dicarboxylic acids. Primary components of Ba, K, Sr, Cl −, Pb, Mg and secondary components of C 5H 6O 4 2−, C 3H 2O 4 2−, C 2O 4 2−, C 4H 4O 4 2−, SO 4 2−, NO 3 − were over five times higher in the lantern days than in the normal days. The firework particles were acidic and of inorganic matter mostly with less amounts of secondary components. Primary aerosols from the burning of fireworks were mainly in the fine mode, while secondary formation of acidic anions mainly took place on the coarse particles. Nitrate was mainly formed through homogeneous gas-phase reactions of NO 2, while sulfate was largely from heterogeneous catalytic transformations of SO 2. Fe could catalyze the formation of nitrate through the reaction of α-Fe 2O 3 with HNO 3, while in the formation of sulfate, Fe is not only the catalyst, but also the oxidant. A simple method using the concentration of potassium and a modified method using the ratio of Mg/Al have been developed to quantify the source contribution of fireworks. It was found that over 90% of the total mineral aerosol and 98% of Pb, 43% of total carbon, 28% of Zn, 8% of NO 3 −, and 3% of SO 4 2− in PM 2.5 were from the emissions of fireworks on the lantern night.

Adsorption and Reaction of SO2 with a Polycrystalline UO2 Film: Promotion of S−O Bond Cleavage by Creation of O-Defects and Na or Ca Coadsorption

To characterize UO(2) for its possible use in desulfurization applications, the interactions of molecular sulfur dioxide (SO(2)) with a polycrystalline uranium dioxide film have been studied by means of X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption (TPD), and low-energy ion scattering (LEIS). The stoichiometric, oxygen-deficient, calcium-precovered and sodium-precovered UO(2) surfaces have been characterized. The changes in oxide reactivity upon creation of oxygen vacancies and coadsorption of sodium and calcium have been studied. After creation of a reduced UO(2-x) surface (x approximately 0.44) via Ar(+) sputtering, the U 4f XPS spectrum shows conspicuous differences that are good indicators of the surface stoichiometry. Molecular SO(x) formation (x = 2-4) is observed after SO(2) deposition onto stoichiometric UO(2) and onto UO(2) precovered with small amounts (<1 ML) of Na or Ca; complete dissociation of SO(2) is not observed. Heating leads to desorption of the SO(x) species and to transformation of SO(2) to SO(3) and SO(3) to SO(4). On oxygen-deficient UO(2) and on UO(2) precovered with large Na or Ca coverages (> or =4 ML), both the formation of SO(x)= species and complete dissociation of SO(2) are observed. A higher thermal stability of the sulfur components is observed on these surfaces. In all cases for which dissociation occurs, the XPS peak of atomic sulfur shows similar structure: three different binding states are observed. The reactivity of oxygen-deficient UO(2) and sodium- and calcium-precovered UO(2) (coverages > or = 4 ML) is attributed to charge transfer into the antibonding LUMO of the adsorbed molecule.

AdS DYNAMICS FOR MASSIVE SCALAR FIELD: EXACT SOLUTIONS vs. BULK-BOUNDARY PROPAGATOR

AdS dynamics for massive scalar field is studied both by solving exactly the equation of motion and by constructing bulk-boundary propagator. A Robertson–Walker-like metric is deduced from the familiar SO (2, n) invariant metric. The metric allows us to present a timelike Killing vector, which is not only invariant under spacelike transformations but also invariant under the isometric transformations of SO (2, n) in certain sense. A horizon appears in this coordinate system. Singularities of field variables at boundary are demonstrated explicitly. It is shown that there is a one-to-one correspondence among the exact solutions and the bulk fields obtained by using the bulk-boundary propagator.

Investigations into formation of atmospheric sulfate under high PM 10 concentration

This study was primarily initiated to understand the consistently low levels of SO 2 in cities in India in spite of rising SO 2 emissions. A literature review suggested the possibility of chemical transformation of SO 2 to SO 4. Thus, the objective of research was to understand the formation of SO 4 as a function of SO 2, and other constituents of atmosphere such as PM 10, water content, Ca (in aerosol) and pH (of aerosol). For this purpose, air quality monitoring was conducted at five locations in the city of Kanpur, India (during October 1999–April 2000) representing various land-use patterns. It was found that the SO 4 levels were considerably high (2.8–43.6 μg m −3) compared to levels in cities in the US (1.9–3.6 μg m −3, Sandberg et al. (J. Air Pollut. Control Assoc. 26 (1976) 559; 15.7–18.4 μg m −3, Altshuller (J. Air Pollut. Control Assoc. 26 (1976) 318; 4.0–14.0 μg m −3 Dockery et al. (J. Med. 329 (1993) 1753), UK (3.2–9.0 μg m −3, QUARG, 1996 http://www.environment.detr.gov.uk/airq/consult/naqs/index.htm), and 25 locations in Europe (0.34–1.68 μg m −3 (1991–1999), EMEP website), but were comparable to the levels observed at Agra (14.67 μg m −3, Kulshrestha et al. Indian J. Radio Space Phys. 24 (1995) 178) and at New Delhi (12.9−27.5 μg m −3, Shandilya, M.E. Thesis, Malaviya National Institute of Technology, Jaipur, India, 2000). The high SO 4 levels could provide a plausible explanation for low SO 2 concentration levels in the city of Kanpur. It was concluded that high levels of PM 10, Ca and high pH of aerosols in atmosphere provide a conducive environment for conversion of SO 2 to SO 4. It was also concluded that the important migration pathway in study area for the transformation of SO 2 to SO 4 appears to be oxidation of SO 2 on the surfaces (of particulate) available in the ambient atmosphere.

Evolution of boundary-layer aerosol particles due to in-cloud chemical reactions during the 2nd Lagrangian experiment of ACE-2

The second Aerosol Characterisation Experiment (ACE-2) was aimed at investigating the physical, chemical and radiative properties of aerosol and their evolution in the North Atlantic region. In the 2nd “Lagrangian” experiment, an air mass was tracked over a 30-h period during conditions of extensive stratocumulus cover. Boundary-layer measurements of the aerosol size distribution obtained with a passive cavity aerosol spectrometer probe (PCASP) during the experiment show a gradual growth in size of particles in the 0.1–0.2 μm diameter mode. Simultaneously, SO 2 concentrations were found to decrease sharply from 800 to 20 ppt. The fraction of sulphate in aerosol ionic mass increased from 0.68±0.07 to 0.82±0.09 for small particles (diameter below 1.7 μm) and from 0.21±0.04 to 0.34±0.03 for large particles (diameter above 1.7 μm). The measurements were compared with a multicyclic parcel model of gas phase diffusion into cloud droplets and aqueous phase chemical reactions. The model was able to broadly reproduce the observed transformation in the aerosol spectra and the timescale for the transformation of SO 2 to sulphate aerosol. The modelled SO 2 concentration in the boundary layer fell to below half its initial value over a 6.5-h time period due to a combination of the entrainment of cleaner tropospheric air and cloud chemical reactions. NH 3 and HCl gas were also found to play an important role in cloud processing in the model. DOI: 10.1034/j.1600-0889.2000.00037.x

Chemical diversity and variation of pyrrolizidine alkaloids of the senecionine type: biological need or coincidence?

Laboratory and field tracer experiments with 14C-labelled senecionine N–oxide (SO) and distant biosynthetic precursors such as [14C]putrescine revealed that pyrrolizidine alkaloid N-oxides (PAs) in Senecio vernalis Waldstr. & Kit. (Asteraceae) show no significant turnover over periods of up to 29 d. However, PAs are spatially mobile, they are continuously allocated, and labelled PAs are even detectable in leaves and capitula developed weeks after tracer application. Chemical diversification of SO, the common product of PA biosynthesis in roots, was studied in five Senecio species (i.e. S. vernalis Waldstr. & Kit., S. vulgaris L, S. inaequidens DC, two chemotypes of S. jacobaea L. and S. erucifolius L.). Tracer experiments revealed that shoots are capable of transforming [14 C]SO into the unique species–specific PA patterns. Within a plant, the transformation efficiency of SO can vary quantitatively and qualitatively between shoot organs (i.e. leaves, stems and inflorescences). All transformations proceed position-specifically and stereoselectively. They comprise simple one-step or two-step reactions such as hydroxylations, epoxidations, dehydrogenations, and O-acetylations, as well as the more complex conversion of the retronecine into the otonecine base moiety (e.g. SO into senkirkine). Taking all the evidence together, the qualitative and quantitative composition of the Senecio PA pattern is a dynamic and sensitive equilibrium between a number of interacting processes: (i) constant rate of de-novo synthesis of SO in roots, (ii) continuous long-distance translocation of SO into shoots, (iii) efficiency of SO transformations which may vary between plant organs, (iv) continuous allocation of PAs in the plant, and (v) efficiency and tissue selectivity of vacuolar storage. We suggest that in constitutive plant defence, without significant turnover of its components, such a highly plastic system provides a powerful strategy to successfully defend and possibly escape herbivory.

Structure/Function Relationships in Ligand-Based SO2/O2 Conversion to Sulfate As Promoted by Nickel and Palladium Thiolates

The dithiolate complex [1,5-bis(mercaptoethyl)-1,5-diazacyclooctane]Pd(II), (bme-daco)Pd{sup II} or Pd-1 whose structure was determined by X-ray crystallography; has been added to a group of metal thiolates which form sulfur-site SO{sub 2} adducts. Exposure of the Pd-1 complex to SO{sub 2} in methanol results in the precipitation of yellow/orange crystalline Pd-1{center_dot}SO{sub 2}. Analogous thiolate-SO{sub 2} adducts based on (bme-daco), Ni-1{center_dot}SO{sub 2}, (Ph{sub 2}PCH{sub 2}CH{sub 2}S){sub 2}Ni{sup II}, Ni-2{center_dot}SO{sub 2}, and (bme*-daco)Ni{sup II}, Ni-1*{center_dot}SO{sub 2}, also precipitate from methanol. To explore the transformation of SO{sub 2} to SO{sub 4}{sup 2-} in these adducts, the following three factors expected to control the sulfate-forming reaction have been examined: (i) the stability of SO{sub 2} adducts; (ii) the oxidizability of the metal thiolate or its tendency to generate disulfide produces on oxidation; and (iii) the ability of the metal thiolates to react with O{sub 2} and produce sulfur-oxygenated products. The studies indicate that the last factor is the most important influence on SO{sub 2} oxygenation. A possible mechanism involves the transient formation of an SO{sub 2}-stabilized sulfperoxide intermediate, which behaves as a nucleophile and further reacts with SO{sub 2} to produce SO{sub 4}{sup 2-}. The use of the aforementioned metal thiolate complexes as catalysts for SO{sub 2}more » oxygenation in the presence of a sacrificial electron donor has also been explored; simple salts such as NiCl{sub 2} and NiSO{sub 4} are more efficient than the complexes.« less

Sulphate-S amendments in soil and their effects on the transformation of soil sulphur

The microbial immobilization and subsequent transformation of SO 2− 4-S were monitored in six soils following amendment with 35S-labelled SO 2− 4-S (20 μg S g −1 soil) with or without glucose (2000 μ g C g −1 soil). In the soils receiving glucose, 21–34% of the added SO 2− 4- 35S was immobilized within 3 days whereas without addition of glucose, only 0.5–13% was immobilized. Similar proportions of the added SO 2− 4 35S were converted into microbial biomass (biomass- 35S) over the same time. Over 127 days, both amendments (with or without glucose) had little effect on soil SO 2− 4-S and extractable-S. There was no measurable effect of the glucose-free amendment on soil biomass-S. However, in soils receiving glucose, total biomass-S increased markedly over the first 3 days (11–24 μg S g −1 soil), whereas in these soils, the amounts of labelled biomass- 35S formed over the same period (3.3–8.7 μg S g −1 soil) were much lower. The additional increase in total biomass-S was due to a priming effect of the glucose amendment on the decomposition of soil organic-S. Between 3 and 10 days, total biomass-S in soils receiving glucose declined to concentrations similar to those in soils receiving the glucose-free amendment. The S (both labelled and unlabelled) lost from this decrease in total biomass-S was converted into soil organic-S since it was undetectable in the SO 2− 4-S pool. The data suggest that the turnover of microbial biomass is the primary process by which S is transformed into soil organic matter.

Identification of Hydroxymethanesulfonate in Fog Water

Previous studies have suggested that hydroxymethanesulfonate ion (HMSA) can be an important species in fog and cloud water. Formation of HMSA explains observed excesses of sulfur in the S(IV) state (+4 oxidation state) and formaldehyde (CH(2)O) in fogs and clouds. HMSA was determined in fog water by a novel ion-pairing chromatographic technique. Concentrations in samples collected in Bakersfield, California, within 5 kilometers of major sources of sulfur dioxide (SO(2)), were as high as 300 micromoles per liter. Total CH(2)O and S(IV) concentrations, which were measured independently, ranged from 10 to 200 and 5 to more than 300 micromoles per liter, respectively. Concentrations of CH(2)O, S(IV), and HMSA at Buttonwillow, California, which is 15 kilometers from the nearest source of SO(2), were less than those at Bakersfield but not absent. These data confirm that HMSA forms in atmospheric water droplets and can reach appreciable concentrations. HMSA represents an important source of acidity for water droplets and may also play a role in long-distance transport and transformation of SO(2).

Ion-induced aerosol formation in a H 2O-H 2SO 4 system—I. Extension of the classical theory and search for experimental evidence

The classical theory of ion-induced nucleation in a H 2SO 4-H 2O mixture is revised and extended for use in a larger range of environmental conditions. Inspired by this theory an experiment has been set up, with the intention to demonstrate the occurrence of aerosol formation through ion-induced nucleation. H 2SO 4 and aerosol particles are continuously formed in a flow reactor by photolytical transformation of SO 2. Upon exposure of this mixture to γ radiation an increase of the particle concentration results. This effect is discussed qualitatively in terms of homogeneous nucleation, ion-induced nucleation and enhanced H 2SO 4 formation.

Southern scandinavian aerosol composition and elemental size distribution characteristics dependence on air-mass history

The influence of aerosol long range transport in southern Sweden was investigated from a data base consisting of simultaneous cascade impactor measurements at three sampling stations, two coastal and one inland rural location. The study focused on S and heavy metals determined by particle induced X-ray emission (PIXE) analysis. The influence of local emissions was minimized by eliminating samples which were strongly suspected to be contaminated. These were identified through size distribution alterations in combination with the concentration levels obtained. Based on air mass back trajectories the samples were classified into either a southern, a northern or an eastern sector or into one of the buffer sectors located in between the sectors mentioned above. Sector S elemental concentrations were generally one order of magnitude higher than those of sector N, while intermediate concentrations were found in the E sector. Intercomparisons of simultaneous fine mode elemental concentration measurements classified into sectors S and N, respectively, provides a method for calculating the sector S foreign contribution of the elemental concentrations in southern Sweden. These calculations, not based on emission data, result in a foreign contribution of the order of 50–90 % (lowest for components like V and Ni and highest for Ti, Mn and Zn) to the metal concentrations. The multivariate statistical method SIMCA revealed that the sector S aerosol elemental composition was dependent on particle size in the accumulation mode. Elements such as S and V (or Ni) normally assumed to originate mainly from the same sources (fossil fuel combustion) were clearly separated and instead S clustered with K, Mn and Zn. This indicates that the transformation processes are more important for the covariation of S with other elements than the source origin. Transformation of SO 2 in hygroscopic particles rich in K., Mn and Zn (compared with less hygroscopic particles rich in V and Ni) is a possible mechanism which would explain the results found.

On rotations in a pseudo-Euclidean space and proper Lorentz transformations

It is shown that in a general pseudo-Euclidean space Epn, 2-flats (planes) passing through the origin of the coordinate system may be classified into six invariant types and explicit formulas for ’’planar rotations’’ in these flats are obtained. In the physically important case of the Minkowski World E34, planar rotations are characterized as rotationlike, boostlike, and singular transformations and an invariant classification of proper Lorentz transformations into these types is given. It is shown that a general nonsingular proper Lorentz transformation may be resolved as a commuting product of two transformations one of which is rotationlike and the other boostlike while a singular transformation may be written as a product of two rotationlike transformations, each with a rotation angle π. Such a rotationlike transformation with angle π is called ’’exceptional’’ following Weyl’s terminology for similar transformations of SO(3). In all cases, explicit formulas for the angles and planes of rotations in terms of the elements of a given Lorentz matrix are obtained and the procedure yields in a natural manner an explicit formula for the image of L in the D10(D01) representation of SO(3,1) which in turn leads to two more classification schemes in terms of the character χ of L in the D10(D01) and the D (1)/(2) 0(D0 (1)/(2) ) representations.

Solution of the steady state, three-dimensional atmospheric diffusion equation for Sulfur dioxide and Sulfate dispersion from point sources

Analytical solutions of the steady state, three-dimensional atmospheric diffusion equation for sulfur dioxide and sulfate dispersion from point sources are presented. First-order transformation of SO 2 to sulfate and wet and dry deposition of both SO 2 and sulfate are included. The solutions permit prediction of the three-dimensional concentration distributions of SO 2 and sulfate downwind of a continuous, elevated point source of SO 2, with or without an elevated inversion layer present.

The measurement of the sulfuric acid and sulfate content of particulate matter resulting from the combustion of coal and oil

Recent evidence has demonstrated a difference between oil and coal combustion emissions of sulfuric acid and inorganic sulfate compounds (primary sulfate emissions). In general, for a given fuel sulfur content, sulfate emissions from residual oil combustion are from 5 to 10 times higher than those from coal. These differences are thought to be due to the increased oxidation of SO 2 by vanadium and nickel found to be present in oil in greater quantities relative to coal. A microdiffusion method for the measurement of total water soluble sulfate and the free sulfuric acid content of combustion particulate has been used as a diagnostic tool to identify boiler/fuel combinations producing significant quantities of primary sulfate emissions. The method accounts for the potential neutralization of acid by the contamination from ammonia during sample preparation and storage. A laboratory study of the recovery efficiencies of H 2SO 4 and (NH 4) 2SO 4 as well as data obtained from the analysis of field samples from coal and oil-fired boilers are discussed. Oil ash samples were found to contain about 20 times more water-soluble sulfate and about 10 times more free sulfuric acid than ash from coal combustion. The results suggest that in areas where the principal sources of ambient suspended particulate matter (TSP) are emissions from fossil fuel combustion, one should expect that the sulfate to TSP ratio is greater for regions dominated by fuel oil usage than in locations using coal. Measurement of the acid and sulfate content of boiler ash could be helpful in identifying individual chemical compound constituents in TSP samples and to elucidate the relative proportion of primary sulfate as compared to sulfate formed by the atmospheric transformation of SO 2.

Large scale spatial and temporal distribution of sulfur compounds

The paper contains new results on the large-scale distribution of SO 2, H 2S and sulfate-aerosols. Recently developed analytical methods permit the measurement of SO 2 in the upper troposphere and lower stratosphere as well as first measurements of the background-concentration of H 2S. Measurements of H 2S close to the ground and in relation to the air-temperature above the ground shows a temperature-dependence of H 2S-release from the soil by biogenic activity. The measurement of sulfateaerosols over the ocean clarified the picture of the formation of maritime sulfate-aerosols and explained the existence of excess sulfate in the maritime atmosphere. Decay of SO 2 and transformation of SO 2 to sulfate was also studied in a meso-scale study over the continent which supplied further information on the influence of anthropogeneous SO 2 sources on the large-scale sulfur budget. Vertical profiles of SO 2 resulting from aircraft measurements over the continent and the Atlantic ocean are compared They are of importance to evaluate the transport and decay of SO 2 over long distances and also indicate the sink function of the ocean surface for the uptake of SO 2.