Emitted sulphur dioxide

Among various reports of relevance to environmental chemistry, the finding by Wallace et al. that tropospheric concentrations of ozone are increased near the plumes of power plants emitting sulphur dioxide is of particular interest. The effect is not caused by photoreactions of SO2 alone, but occurs with SO2 in the presence of CI2. A chain process involving ClOO radicals may be involved. Of more distant relevance is the observation by Ferris and Benson that photolysis of PHj to P2H4 appears to play a part in the atmospheric photochemistry of the planet Jupiter. 

In the U.K. in 1992, 3.5 million tonnes of sulphur dioxide were emitted into the atmosphere. Combustion of fossil fuels in electricity generating power stations produced 69% of the emitted sulphur dioxide. Much of this sulphur dioxide is oxidized in the atmosphere, e.g. by ozone, eventually to produce sulphuric acid or sulphates. 

In 1985, about 70% of the sulphur dioxide in the United States was emitted from fossil-fueled generating stations while in Canada, about 50% was... 

Experiment.—Qninol from Quinone. Suspend about 2 g. of quinone in 50 c.c. of water and while shaking frequently saturate the suspension with sulphur dioxide. Keep for some time and then extract the now colourless liquid twice with ether, dry the ethereal extract with calcium chloride, and evaporate the ether. The residue of quinol crystallises. Recrystallise it from a little water. Melting point 169°. Warm a sample with dilute sulphuric acid and a few drops of dichromate solution the odour of quinone is emitted. 

When sulphur dioxide alone is passed over carbon at a red heat the latter undergoes partial oxidation, the products being carbon monoxide, carbon oxysulphide and carbon disulphide no oxysulphide is obtained at a white heat.2 Both carbon monoxide and methane are oxidised by sulphur dioxide at high temperatures with formation of sulphur. It has been suggested that volcanic sulphur may, in part, be formed by the reduction of sulphur dioxide by methane, carbon monoxide and hydrogen, all of which are emitted by volcanoes.4... 

Sulphur dioxide is both emitted into the troposphere and also formed during oxidation of dimethyl sulphide (DMS) and other sulphur containing species produced in the biosphere. Important sources of atmospheric S02 are volcanoes. However, the major single global source is probably the combustion of sulphur-containing fossil fuels. In the stratosphere there are two important sources of sulphur dioxide, i.e. injection by volcanic eruptions and oxidation of carbonyl sulphide (COS), which is transported from the troposphere. 

Sulphur colouring matters are more or less soluble in water, but readily soluble in alkalies or alkaline sulphides when treated with hydrochloric acid or, better, with hydrochloric add and stannous chloride, they emit hydrogen sulphide when burnt they give an odour of sulphur dioxide and leave a more or less abundant residue containing alkaline sulphates and sulphites. 

By whatever route, whether wet or dry deposition, ultimately aU the sulphur dioxide emitted into the atmosphere comes back to the earth s surface in one form... 

The behaviour of the oxides of nitrogen emitted from a source of pollution is much more complicated than for sulphur dioxide. The oxides of nitrogen are much more chemically reactive and form a whole family of oxidised nitrogen compounds. Each family member has a different fate and behaviour. Dry deposition and wet deposition occur downwind from the NO, source through the respective contributions from nitrogen dioxide, nitric acid and nitrate aerosol [17]. 

Where, then, did our modern atmosphere come from The answer seems to be volcanoes. As well as emitting sulphurous fumes (which would have precipitated in the rain), volcanic gases include nitrogen and carbon dioxide (in about the right balance), tiny amounts of neon, and almost no methane, ammonia or oxygen. 

The effects of low concentrations of sulphur dioxide upon the rates of O3 and NO formation in irradiated mixtures of NO2 and air have been investigated, in an effort to determine the reasons for formation of increased tropospheric concentrations of O3 near the plumes of power plants emitting S02. No such effects were observed for SO2 concentrations up to lOp.p.m. when the experiments were repeated with added Cl2 however an increase in the O3 concentration was observed, and a chain-reaction mechanism involving formation of the ClOO species has been suggested to explain the observations. Further two-dimensional modelling calculations of O3 depletion rates have been described. The importance of establishing the fraction F of the removal rate of 0( D) by N2O... 

Sulphur dioxide is the main harmful substance emitted by industry, as regards its amounts in the atmosphere. The amount of sulphur emitted into the atmosphere, mainly as sulphur dioxide, is even greater than that utilized in the conversion to sulphuric acid or other sulphur compounds. This results particularly from high contents of sulphur in the coal and petroleum burned and from an insufficient retention of sulphur dioxide from combustion products. Sulphur dioxide affects plants as well as animals. It is of primary importance in industrial toxicology from the local, regional and also global standpoints. 

Metal sulphides. Many metals (e.g., iron, copper, lead, nickel) are found as mineral ores in sulphide form (pyrites) of which iron sulphide is most common. These are concentrated by physical and chemical means to produce an ore ready for economical extraction. Some may be subject to oxidation to generate heat, deplete oxygen, and emit toxic fumes. Calcined pyrites are used in the production of sulphuric acid and sulphur dioxide. In the presence of moisture, the calcined residue or dust can generate acids. 

Steam may account for over 90% of the gases emitted during a volcanic eruption. Other gases present include carbon dioxide, carbon monoxide, sulphur dioxide, sulphur trioxide. 

The gas phase oxidation of sulphur dioxide has probably been studied in more detail than any other atmospheric species. In general terms the types of reaction are also appropriate to NO They involve the oxidation of sulphur dioxide and NO by free radicals - namely the hydroxyl radical generated by the photolysis of ozone - to form an acid aerosol. In polluted atmospheres where there are larger quantities of NO and hydrocarbons generating photo-oxidants/ there is evidence to suggest that the aerosols formed will be a mixture of sulphuric and nitric acids. In other words/ the conversion process to sulphates and nitrates will take place much more readily when the acid pollutants emitted pass through polluted air (more likely to be over land/ than over water). 

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