Sulfur dioxide anthropogenic sources

The production of acid rain starts when atmospheric sulfur dioxide is oxidized to sulfur trioxide in a complex series of reactions. SO3 is, in turn, hydrolyzed to sulfuric acid. Anthropogenic sources of sulfur dioxide include the burning of coal, the refining and burning of oil, and the smelting of copper ores. Until control measures started to come on line, the pH of rainwater in the northeastern United States and other areas downwind of such sources had fallen to values between 3 and 4. The best control measures have proven to be wet and dry scrubbers. As a result of installation of these flue-gas desulfurization (FGD) devices, the amount of sulfur and nitrogen oxides released to the atmosphere has measurably decreased in the last several decades. 

A substantial portion of fhe gas and vapors emitted to the atmosphere in appreciable quantity from anthropogenic sources tends to be relatively simple in chemical structure carbon dioxide, carbon monoxide, sulfur dioxide, and nitric oxide from combustion processes hydrogen sulfide, ammonia, hydrogen chloride, and hydrogen fluoride from industrial processes. The solvents and gasoline fractions that evaporate are alkanes, alkenes, and aromatics with relatively simple structures. In addition, more complex... 

Sulfur dioxide is produced by both natural and anthropogenic sources. The most important of the natural sources are volcanic eruptions, which account for about 40 percent of all natural emissions of the gas. Since volcanic eruptions are episodic events, the amount of sulfur dioxide attributable to this source in any one year varies widely. Other natural sources of the gas are forest fires and other natural burns, biological decay, and certain metabolic processes carried out by living organisms, especially marine plankton and bacteria. Natural sources release about 27.5 million short tons (25 million metric tons) of sulfur dioxide per year. 

The most important anthropogenic source of sulfur dioxide are power generating plants, which account for about 70 percent of all the gas produced in the United States. Another 25 percent of the sulfur dioxide emitted in the country is from a variety of industrial and manufacturing operations. Less than 5 percent of the gas is produced by motor vehicles and other forms of transportation. 

The global natural flux of sulfur compounds to the atmosphere has recently been estimated to be about 2.5 Tmol yr1 (1) which is comparable to the emissions of sulfur dioxide (SO2) from anthropogenic sources (2). A substantial amount of the natural sulfur contribution (0.5-1.2 Tmol yr1) is attributed to the emission of dimethylsulfide (DMS) from the world s oceans to the atmosphere (3.4). One of the major uncertainties in this estimate is due to a scarcity of DMS and other sulfur data from the Southern Hemisphere, particularly the Southern Ocean region between about 40°S and the Antarctic continent, which represents about one fifth of the total world ocean area. 

In the last 150 years the anthropogenic emission of sulfur has increased dramatically, primarily due to combustion processes [1]. In the 1950s anthropogenic emission surpassed natural emission and the atmospheric sulfur cycle is one of the most perturbed biogeochemical cycles [1,2]. The oceans are the largest natural source of atmospheric sulfur emissions, where sulfur is emitted in a reduced form, predominantly as dimethyl sulfide (DMS) and to a much lesser extent carbonyl sulfide (OCS) and carbon disulfide (CS2) [3]. Ocean emitted DMS and CS2 are initially oxidised to OCS, which diffuses through the troposphere into the stratosphere where further oxidation to sulfur dioxide (SO2), sulfur trioxide (SO3) and finally sulfuric acid (H2SO4) occurs [1-4]. 

Volcanoes and to a small extent biomass burning represent the major natural primary sources of sulfur dioxide to the atmosphere. Further sulfur dioxide is produced through the oxidation of sulfides, in the atmosphere. In addition to the natural sources there is a very large anthropogenic source that arises from fossil fuel combustion that is comparable in magnitude to the natural sources. 

Large quantities of sulfur dioxide enter the atmosphere each year from anthropogenic sources, mainly the combustion of fossil fuels and the smelting of metals. S02 indisputably ranks as a prominent pollutant, and it is understandable that research of the past 30 yr dealing with atmospheric sulfur has concentrated on such problems as the dispersal of S02 from power stations and urban centers, its conversion to sulfuric acid, the formation of sulfate aerosols, and the deposition of sulfate and S02 at the ground surface. 

The major anthropogenic sources of sulfur dioxide emissions are fossil fuel and biomass burning, iron and non-ferrous metal smelting and sulfur acid production. The natural emissions from volcano eruptions and massive forest fires should be also taken into account if any occur in the considered period. 

Sulfur Dioxide Sulfur dioxide (SO2) has many anthropogenic sources including the combustion of coal and oil containing sulfur. It is also emitted during metal-smelting processes, petrochemical, pulp, and paper industries. 

What is the main source of anthropogenic sulfur dioxide in Earth s atmosphere ... 

When coal—which is mostly carbon—bums, sulfur burns along with it to form sulfur dioxide (SO ). In the atmosphere, the reactions previously shown take place as winds blow SO, SO3, and H SO hundreds of miles from their sources. like H SO from natural sources, H SO from anthropogenic sources washes from the atmosphere in the next rain, sleet, or snowstorm. 

---