Sulfur dioxide volcanic

Sulfur dioxide occurs in industrial and urban atmospheres at 1 ppb—1 ppm and in remote areas of the earth at 50—120 ppt (27). Plants and animals have a natural tolerance to low levels of sulfur dioxide. Natural sources include volcanoes and volcanic vents, decaying organic matter, and solar action on seawater (28,290,291). Sulfur dioxide is beHeved to be the main sulfur species produced by oxidation of dimethyl sulfide that is emitted from the ocean. 

Sulfur forms several oxides that in atmospheric chemistry are referred to collectively as SOx (read sox ). The most important oxides and oxoacids of sulfur are the dioxide and trioxide and the corresponding sulfurous and sulfuric acids. Sulfur burns in air to form sulfur dioxide, S02 (11), a colorless, choking, poisonous gas (recall Fig. C.1). About 7 X 1010 kg of sulfur dioxide is produced annually from the decomposition of vegetation and from volcanic emissions. In addition, approximately 1 X 1011 kg of naturally occurring hydrogen sulfide is oxidized each year to the dioxide by atmospheric oxygen ... 

Sulfur dioxide Is formed primarily from the Industrial and domestic combustion of fossil fuels. On a global scale, man-made emissions of SOj are currently estimated to be 160-180 million tons per year. These emissions slightly exceed natural emissions, largely from volcanic sources. The northern hemisphere accounts for approximately 90% of the man-made emissions (13-14). Over the past few decades global SOj emissions have risen by approximately 4%/year corresponding to the Increase In world energy consumption. 

Acid rain is actually a catchall phrase for any kind of acidic precipitation, including snow, sleet, mist, and fog. Acid rain begins when water comes into contact with sulfur and nitrogen oxides in the atmosphere. These oxides can come from natural sources such as volcanic emissions or decaying plants. But there are man-made sources as well, such as power plant and automobile emissions. In the United States, two-thirds of all the sulfur dioxide and one-fourth of the nitrogen oxides in the atmosphere are produced by coal-burning power plants. 

During a volcanic eruption, a lot of ash is blasted into the atmosphere. The gases, such as sulfur dioxide and radon, remain invisible. 

Acid rain is caused primarily by sulfur dioxide emissions from burning fossil fuels such as coal, oil, and natural gas. Sulfur is an impurity in these fuels for example, coal typically contains 2-3% by weight sulfur.1M Other sources of sulfur include the industrial smelting of metal sulfide ores to produce the elemental metal and, in some parts of the world, volcanic eruptions. When fossils fuels are burned, sulfur is oxidized to sulfur dioxide (SO2) and trace amounts of sulfur trioxide (SC>3)J21 The release of sulfur dioxide and sulfur trioxide emissions to the atmosphere is the major source of acid rain. These gases combine with oxygen and water vapor to form a fine mist of sulfuric acid that settles on land, on vegetation, and in the ocean. 

Sulfur has four unique characteristics related to its occurrence and chemistry in soil. As sulfate, it is one of the principle counterions that keep the soil electrically neutral. Soil receives constant additions of sulfur through volcanic activity around the world and industrial pollution, usually in the form of acid rain. This means that soils usually have sufficient sulfur for plant growth. Lastly, plants can take and use sulfur dioxide from the air as a source of sulfur for growth [22,38],... 

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. 

Sny material in the atmosphere that is harmful to health is defined as an air pollutant. One major source of air pollutants is volcanoes. The largest volcanic blast of the 20th century, for example, was the 1991 eruption of Mount Pinatubo in the Philippines, which released 20 million tons of the noxious gas sulfur dioxide, S02. As Figure 17.7 shows, this sulfur dioxide managed to travel all the way to India in only 4 days. 

Krueger, A.J., L.S. Walter, P.K. Bhartia, C.C. Schnetzler, N.A. Krotkov, I. Sprod and G.J.S. Bluth (1995) Volcanic sulfur dioxide measurements from the total ozone mapping spectrometer (TOMS) instruments. Journal of Geophysical Research 100 14057-14076. 

About 4500 million years ago the Earth was formed. Over a period of time, the Earth cooled to become a molten mass upon which a thin crust formed. Volcanic activity through the crust pushed out huge quantities of gases, such as ammonia, nitrogen, methane, carbon monoxide, carbon dioxide and a small amount of sulfur dioxide, which formed an atmosphere around the Earth (Figure 11.3). 

The fact that sulfur is often found in areas of volcanic activity may be due to the reaction of sulfur dioxide, S02, and hydrogen sulfide, H2S, both gases being found in volcanic emissions. One such reaction can be represented by the equation... 

DMS) Sulfur dioxide Oxidation of H2S volcanic Combustion of oil and coal ... 

Some diverse VOCs (halocarbons, isoprene (CH2C(CH3) CH2CH2), monoterpenes, ethanol, and methyl tert-butyl ether, (CHslsCOCHs)) were found to be photooxidized efficiently on solid aerosols. Solid photocatalyst particles, such as Ti02, ZnO, and Fe20s, were here of special importance, but the VOC oxidation was photoassisted also by dessert sand, volcanic ash, or even by chalk particles (23-25). Similarly, sulfur dioxide was found to... 

CarnS. A., Krueger A. J., Bluth G. J. S., Schaefer S. J., Krotkov N. A., Watson 1. M., and Datta S. (2003) Volcanic eruption detection by the Total Ozone Mapping Spectrometer (TOMS) instruments a 22-year record of sulfur dioxide and ash emissions. In Volcanic Degassing. Geological Society of London Special Publication 213 (eds. C. Oppenheimer, D. M. Pyle, and J. Barclay). Geological Society of London, 177-202. 

Oppenheimer C., Francis P., and Stix J. (1998b) Depletion rates of sulfur dioxide in tropospheric volcanic plumes. Geophys. Res. Lett. 25, 2671-2674. 

Wallace P. J. and Gerlach T. M. (1994) Magmatic vapor source for the sulfur dioxide released during volcanic eruptions evidence from Mount Pinatubo. Science 265, 497-499. 

Winner W. E. and Mooney H. A. (1980) Responses of Hawaiian plants to volcanic sulfur dioxide stomatal behavior and foliar injury. Science 210, 789-791. Zdanowicz C. M., Zielinski G. A., and Germani M. S. (1999) Mt. Mazama eruption calendrical age verified and atmospheric impact assessed. Geology 27, 621-624. 

When we consider of the heterogeneous oxidation of SO2, it has to include not only the oxidation of the SO2 within the droplet phase, but the transfer of further SO2 into the droplet and the overall depletion of the gas in the air mass as a whole. In general the overall oxidation in the remote atmosphere is rather slow and takes 2-4 d, but under some conditions it can be much faster. The depletion rates of sulfur dioxide in volcanic plumes can sometimes be very fast with residence times of as little as 15 min in moist plumes, where catalytic mechanisms similar to urban air masses probably occur. 

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