Anthropogenic contributions to global carbonyl sulfide, carbon disulfide and organosulfides fluxes

Previous studies of the global sulfur cycle have focused almost exclusively on oxidized species and just a few sulfides. This focus is expanded here to include a wider range of reduced sulfur compounds. Inorganic sulfides tend to be bound into sediments, and sulfates are present both in sediments and the oceans. Sulfur can adopt polymeric forms that include S-S bonds. This review examines the global anthropogenic sources of reduced sulfur, updating emission inventories and widening the consideration of industrial sources. It estimates the anthropogenic fluxes of key sulfides to the atmosphere (units Gg S a-1) as: carbonyl sulfide (total 591: mainly from pulp and pigment 171, atmospheric oxidation of carbon disulfide 162, biofuel and coal combustion, 133, natural 898 Gg S a-1), carbon disulfide (total 746: rayon 395, pigment 205, pulp 78, natural 330 Gg S a-1), methanethiol (total 2119: pulp 1680, manure 330, rayon and wastewater 102, natural 6473 Gg S a-1), dimethyl sulfide (total 2197: pulp 1462, manure 660 and rayon 36, natural 31 657 Gg S a-1), dimethyl disulfide (total 1103: manure 660, pulp 273; natural 1081 Gg S a-1). The study compares the magnitude of the natural sources: marine, vegetation and soils, volcanoes and rain water with the key anthropogenic sources: paper industry, rayon-cellulose manufacture, agriculture and pigment production. Industrial sources could be reduced by better pollution control, so their impact may lessen over time. Anthropogenic emissions dominate the global budget of carbon disulfide, and some aromatic compounds such as thiophene, with emissions of methanethiol and dimethyl disufide also relatively important. Furthermore, industries related to coal and bitumen are key sources of multi-ringed thiophenes, while food production and various wastes may account for the release of significant amounts of dimethyl disulfide and dimethyl trisulfide

Short-Lived Trace Gases in the Surface Ocean and the Atmosphere

The two-way exchange of trace gases between the ocean and the atmosphere is important for both the chemistry and physics of the atmosphere and the biogeochemistry of the oceans, including the global cycling of elements. Here we review these exchanges and their importance for a range of gases whose lifetimes are generally short compared to the main greenhouse gases and which are, in most cases, more reactive than them. Gases considered include sulphur and related compounds, organohalogens, non-methane hydrocarbons, ozone, ammonia and related compounds, hydrogen and carbon monoxide. Finally, we stress the interactivity of the system, the importance of process understanding for modeling, the need for more extensive field measurements and their better seasonal coverage, the importance of inter-calibration exercises and finally the need to show the importance of air-sea exchanges for global cycling and how the field fits into the broader context of Earth System Science

The tropospheric oxidation of dimethyl sulfide: A new source of carbonyl sulfide

In laboratory investigations of the gas-phase OH initiated oxidation of dimethyl sulfide (DMS: CH3SCH3) at room temperature the formation of SO2, dimethyl sulfoxide (DMSO: CH3SOCH3), and OCS have been observed. A yield of 0.7±0.2% S was measured for OCS. These new results represent a hitherto unknown and quite considerable in situ atmospheric source of OCS. Based on the global DMS source strength as given in the literature and provided that the results from the laboratory study are valid under atmospheric conditions we estimate a contribution in the range 0.10 to 0.28 Tg (OCS) yr−1 from the gas-phase atmospheric photooxidation of DMS to the global OCS budget

Heavy metals contamination of soils surrounding waste deposits in Romania

Soils contamination with heavy metals is one of the most severe aspects of environmental pollution in Romania, independently of the origin sources (domestic or industrial activities) or type of disposal (organised landfill or hazardous deposits)[l-2]. This fact is the consequence of the poor state of the existing waste deposits in Romania and of the significant costs involved by the establishing of a new landfill according with the international regulations. The present study is trying to emphasise the contamination of soils surrounding different categories of waste deposits (sewage sludge ponds, domestic and industrial waste landfills, hillocks, sterile deposits) from various regions of Romania. Some case studies show a special interest being localise in a protected area (Iron Gates Natural Park). In order to quantify the concentration of metals like Cd, Cr, Cu, Pb, Zn, Ni, Mo in soil samples, analysis were performed using Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES). Romanian standards were used as reference values [3]

FTIR Kinetic and Mechanistic Study of the Atmospheric Chemistry of Methyl Thiolformate

Some aspects of the atmospheric chemistry of methyl thiolformate (CH3SCHO), a recently detected intermediate in the oxidation of dimethyl sulfide, have been investigated at 298 K and 1000 mbar total pressure in large reaction chambers using long path in situ FTIR absorption spectroscopy for the analysis. Rate coefficients of (1.11 ± 0.22) × 10-11 and (5.80 ± 0.80) × 10-11 cm3 molecule-1 s-1 have been determined for its reaction with OH radicals and Cl atoms, respectively. The UV spectrum of CH3SCHO has been measured in the range 220−355 nm and a lower limit of 5.4 days determined for its atmospheric photolytic lifetime. Detailed product analyses have made for the OH and Cl initiated photooxidation of CH3SCHO. Strong SO absorption bands observed in both systems are tentatively assigned to CH3SOCHO in the OH system and to CH3SOCl in the Cl system. The first gas-phase spectra of CH3SCl and CH3SOCl are also presented. The results are discussed with respect to the atmospheric chemistry of CH3SCHO and possible consequences for the photooxidation mechanism of dimethyl sulfide

Reaktionen von organischen Schwefelverbindungen

Due to the lack of information on intermediates and end products in the oxidation of DMS, further investigations on these processes are needed. The purposes of the present work are as follows: - To clarify the formation of dimenthyl sulphoxide, a missing product of the addition pathway in the OH-initiated oxidation of DMS. - To study how the concentration of O_2 and NO_x influences the production of DMSO in order to obtain information about the reaction of the DMS-OH adduct with O_2 and NO_x. - To study how the oxidation of DMSO itself contributes to the end product distribution in the oxidation of DMS. - To look for some other proposed but unidentified products like OCS and MTF, possible products of the abstraction channel in the oxidation of DMS and to identify the precursors of these compounds. - To investigate the possible fate of DMSO and MTF in the oxidation system of DMS, i.e. the OH-initiated oxidation of DMSO and MTF. - Because no data are available on the atmospheric chemistry of MTF yet, its reactions with NO_3 at Cl atoms will also be studied. (orig.)Available from TIB Hannover: RO 974(35) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Atmospheric oxidation of α,β-unsaturated ketones: Kinetics and mechanism of the OH radical reaction

The OH-radical-initiated oxidation of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one was investigated in two atmospheric simulation chambers at 298±3 K and 990±15 mbar using long-path FTIR spectroscopy. The rate coefficients of the reactions of 3-methyl-3-penten-2-one and 4-methyl-3-penten-2-one with OH radicals were determined to be (6.5±1.2)×10-11 and (8.1±1.3)×10-11 cm3molecule-1s-1, respectively. To enlarge the kinetics data pool the rate coefficients of the target species with Cl atoms were determined to be (2.8±0.4)×10-10 and (3.1±0.4)×10-10 cm3molecule-1s-1, respectively. The mechanistic investigation of the OH-initiated oxidation focuses on the RO2+NO reaction. The quantified products were acetoin, acetaldehyde, biacetyl, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 3-methyl-3-penten-2-one with OH radicals and acetone, methyl glyoxal, 2-hydroxy-2-methylpropanal, CO2 and peroxyacetyl nitrate (PAN) for the reaction of 4-methyl-3-penten-2-one with OH, respectively. Based on the calculated product yields an upper limit of 0.15 was determined for the yield of RONO2 derived from the OH reaction of 4-methyl-3-penten-2-one. By contrast, no RONO2 formation was observed for the OH reaction of 3-methyl-3-penten-2-one. Additionally, a simple model is presented to correct product yields for secondary processes.Fil: Niklas, Illmann. Physikalische Chemie, Bergische Universität Wuppertal,; AlemaniaFil: Gibilisco, Rodrigo Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Bejan, Iustinian Gabriel. Faculty Of Chemistry And Environment Studies; RumaniaFil: Patroescu Klotz Iulia. Physikalische Chemie, Bergische Universität Wuppertal,; AlemaniaFil: Wiesen, Peter. Physikalische Chemie, Bergische Universität Wuppertal,; Alemani

Ausbeuten von Aerosolvorlaeufersubstanzen bei der DMS-Oxidation als Funktion von atmosphaerischen Bedingungen (Temperatur und NO_x) Abschlussbericht

In-depth analyses have been made of the products and aerosol formation from the OH-radical initiated oxidation of dimethyl sulphide (CH3SCH3: DMS) as a function of temperature, O2 partial pressure and initial NO concentration in large photoreactors. The investigations have provided new insights into the oxidation mechanisms of both DMS and DMSO, e.g., it has been shown that interactions of the DMS-OH adduct with O2 form DMSO in the absence of NO and dimethyl sulphone (CH3SO2CH3: DMSO2) in its presence. The data support an SO2 yield of around 70% from OH + DMS in the remote marine atmosphere. Investigations on the OH-radical initiated oxidation of dimethyl sulphoxide (CH3SOCH3: DMSO) have shown for the first time that methane sulphinic acid (CH3S(O)OH: MSIA) is the major product. Within the experimental conditions employed in the experiments only a modest dependence of the aerosol yield on temperature and initial NO concentration was observed. The experiments support that sulphuric acid formed from OH + SO2 is the major component of the aerosol with only minor contributions from MSA and MSIA. The mechanistic information is being incorporated into a DMS atmospheric chemistry modeule for CTMs (http://www.dmi.dk/f+u/luft/eng/elcid/elcid.html target=NewWindow> http://www.dmi.dk/f+u/luft/eng/elcid/elcid.html ) and also in a simplified form for a global climate model (http://ask.ii.uib.no/.climate/elcid/ target=NewWindow> http://ask.ii.uib.no/.climate/elcid/ ). (orig.)SIGLEAvailable from TIB Hannover: F02B1558 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung und Forschung, Berlin (Germany)DEGerman

Preparation of Experiments: Addition and In Situ Production of Trace Gases and Oxidants in the Gas Phase

Abstract Preparation of the air mixture used in chamber experiments requires typically the injection of trace gases into a bath gas. In this chapter, recommendations and standard protocols are given to achieve quantitative injections of gaseous, liquid or solid species. Various methods to produce ozone, nitrate radicals and hydroxyl radicals are discussed. Short-lived oxidants need to be produced during the experiment inside the chamber from pre-cursor species. Because highly reactive oxidants like hydroxyl radicals are challenging to detect an alternative method for the quantification of radical concentrations using trace molecules is described