Sulfur dioxide, air pollution

Sulfur dioxide enters the atmosphere as a result of the following  

The pollutant sources are of most concern because of their contribution to local and regional air pollution problems and because they are sources that humans can do something about. 

The fate of sulfur dioxide in the atmosphere is oxidation and reaction with water to produce sulfuric acid. The overall process is complex, but it can be described by the following reaction  

In addition to indirect effects from the formation of acid rain, sulfur dioxide affects some plants directly, causing leaf necrosis (death of leaf tissue). Another symptom of sulfur dioxide phytotoxicity (toxicity to plants) is chlorosis, a bleaching or yellowing of green leaves. 

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Fluid bed boilers have also been applied as a cure to sulfur dioxide air pollution from power plants. Various schemes have been developed in which combustion of a sulfur containing fuel takes place in a fluidized bed of particles which absorb or react with sulfur dioxide. The particles are usually regenerated to recover sulfur, which often has enough by-product value to make a significant contribution to process economics. 

Containing Oxides of Nitrogen and Sulfur Dioxide, Air Pollution Foundation Report No. 29, San Marino, California, October 1959. 

Qualitative Scale for the Estimation of Sulfur Dioxide Air Pollution IN England and Wales Using Epiphytic Lichens"... 

Hawksworth, D. L., and Rose, F. (1970). Qualitative scale for estimating sulfur dioxide air pollution in England and Wales using epiphytic lichens. Nature (London) 221 y 145-148. 

The NAAQS in effect as of June 2004 are summarized in the chart on pages 53-54. Note that only six air pollutants are included in this table carbon monoxide, nitrogen dioxide, ozone, lead, particulate matter, and sulfur dioxide. These pollutants are called criteria pollutants. 

Reporting of concentrations of one gas in another on a volume for volume basis is normally corrected to 25°C and 1 atm (760 mm Hg) pressure [22, 23]. Under this system, relatively high concentrations are specified in percent so that 3% sulfur dioxide in air would correspond to 3 mL of sulfur dioxide mixed with 97 mL of air, both specified at 25°C and 1 atm. This also corresponds to 3 parts by volume of sulfur dioxide in 100 parts by volume of the sulfur dioxide/air mixture, both specified in the same volume units. Lower concentrations are specified in smaller units, ppm (or ppmv, v for volume) for parts per million (1 in 10 ), ppb for parts per billion (1 in 10 ), and even ppt for parts per trillion (1 in 10 ), now that adequate sensitivity has been developed for the analysis of some air pollutants at these low concentrations. 

In the presence of certain catalysts, sulfur dioxide in polluted air reacts rapidly with O2 to form SO3. Particulate matter, or suspended microparticles, such as NH4NO3 and elemental S, act as efficient catalysts. 

The earliest reports of acute environmental incidents were of air pollution emergencies. In the Meuse Valley of Belgium during 1930, 63 persons died and thousands became ill from sulfur dioxide and sulfuric acid air pollution (French 1989). The Donora, Pennsylvania, smog disaster in 1948 left 20 dead and more than 5,000 ill (French 1989). 

Sulfur dioxide is the predominant anthropogenic sulfur-containing air pollutant. Mixing ratios of SO2 in continental background air range from 20 ppt to over 1 ppb in the unpolluted marine boundary layer levels range between 20 and 50 ppt. Urban SO2 mixing ratios can attain values of several hundred parts per billion. We will consider the atmospheric chemistry of SO2 in Chapter 5. 

Primary pollutants are emitted directly from the sources and remain unchanged once they enter the environment. Examples include particulate matter and inorganic gases, such as sulfur dioxide. Secondary pollutants, for example sulfurous acid, are formed in the atmosphere by chemical reactions involving primary pollutants and gases normally present in the air. 

If 50.0 g of sulfur dioxide from pollutants reacts with water and oxygen found in the air, how many grams of sulfuric acid can be produced How many grams of oxygen are used in the process ... 

It quickly deadens the sense of smell. Sulfur dioxide is a dangerous component in atmospheric air pollution. 

Air Pollution. Particulates and sulfur dioxide emissions from commercial oil shale operations would require proper control technology. Compliance monitoring carried out at the Unocal Parachute Creek Project for respirable particulates, oxides of nitrogen, and sulfur dioxide from 1986 to 1990 indicate a +99% reduction in sulfur emissions at the retort and shale oil upgrading faciUties. No violations for unauthorized air emissions were issued by the U.S. Environmental Protection Agency during this time (62). 

The absorption of sulfur dioxide in alkaline (even weakly alkaline) aqueous solutions affords sulfites, bisulfites, and metabisulfites. The chemistry of the interaction of sulfur dioxide with alkaline substances, either in solution, slurry, or soHd form, is also of great technological importance in connection with air pollution control and sulfur recovery (25,227,235—241). Even weak bases such as 2inc oxide absorb sulfur dioxide. A slurry of 2inc oxide in a smelter can be used to remove sulfur dioxide and the resultant product can be recycled to the roaster (242). 

Sulfur Dioxide Emissions and Control. A substantial part of the sulfur dioxide in the atmosphere is the result of burning sulfur-containing fuel, notably coal, and smelting sulfide ores. Methods for controlling sulfur dioxide emissions have been reviewed (312—314) (see also Air POLLUTION CONTROL PffiTHODS COAL CONVERSION PROCESSES, CLEANING AND DESULFURIZATION EXHAUST CONTROL, INDUSTRIAL SULFURREMOVAL AND RECOVERY). 

ERA promulgated the basic set of current ambient air-quality standards in April 1971. The specific regulated pollutants were particulates, sulfur dioxide, photochemical oxidants, hydrocarbons, carbon monoxide, and nitrogen oxides. In 1978, lead was added. Table 25-1 enumerates the present standards. 

Human-made sources cover a wide spectrum of chemical and physical activities and are the major contributors to urban air pollution. Air pollutants in the United States pour out from over 10 million vehicles, the refuse of over 250 million people, the generation of billions of kilowatts of electricity, and the production of innumerable products demanded by eveiyday living. Hundreds of millions of tons of air pollutants are generated annu ly in the United States alone. The five main classes of pollutants are particulates, sulfur dioxide, nitrogen oxides, volatile organic compounds, and carbon monoxide. Total emissions in the United States are summarized by source categoiy for the year 1993 in Table 25-10. 

Sufficient evidence is available to indicate that atmospheric pollution in vaiying degrees does affect health adversely. [Amdur, Melvin, and Drinker, Effec t of Inhalation of Sulfur Dioxide by Man, Lancet, 2, 758 (1953) Barton, Corn, Gee, VassaUo, and Thomas, Response of Healthy Men to Inhaled Low Concentrations of Gas-Aerosol Mixtures, Arch. Lnviron. Health, 18, 681 (1969) Bates, Bell, Burnham, Hazucha, and Mantha, Problems in Studies of Human Exposure to Air Pollutants, Can. Med. A.s.soc. J., 103, 833 (1970) Ciocco and... 

The problems with the combustion reaction occur because the process also produces many other products, most of which are termed air pollutants. These can be carbon monoxide, carbon dioxide, oxides of sulfur, oxides of nitrogen, smoke, fly ash, metals, metal oxides, metal salts, aldehydes, ketones, acids, polynuclear hydrocarbons, and many others. Only in the past few decades have combustion engineers become concerned about... 

An air pollution episode responsible for approximately 300 excess deaths occurred in London between November 26 and December 1, 1948. Concentrations of smoke and sulfur dioxide were 50-70% of the values during the 1952 episode. 

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