Pollutants sulfur dioxide

Haider SS, Hasan M. 1984. Neurochemical changes by inhalation of environmental pollutants sulfur dioxide and hydrogen sulfide Degradation of total lipids, elevation of lipid peroxidation and enzyme activity in discrete regions of the guinea pig brain and spinal cord. Ind Health 22 23-31. 

However, more than one reaction pathway may exist, in which case the rate equation will contain sums of terms representing the competing reaction pathways. For example, one of the oxidation reactions that convert the atmospheric pollutant sulfur dioxide to sulfuric acid (a component of acid rain) in water droplets in clouds involves dissolved ozone, O3 (see Sections 8.3 and 8.5) ... 

Sulfur S 16 32.064 Essential element, occurs in air pollutant sulfur dioxide, S02... 

The definition of environmental chemistry given above is illustrated for a typical environmental pollutant in Figure 2.3. Pollutant sulfur dioxide is generated in the anthrosphere by combustion of sulfur in coal, which has been extracted from the geosphere. The S02 is transported to the atmosphere with flue gas and oxidized by chemical and photochemical processes in the atmosphere to sulfuric acid. The sulfuric acid, in turn, falls as acidic precipitation, where it may have detrimental effects, such as toxic effects, on trees and other plants in the biosphere. Eventually the sulfuric acid is carried by stream runoff in the hydrosphere to a lake or ocean, where its ultimate fate is to be stored in solution in the water or precipitated as solid sulfates and returned to the geosphere. 

Properties of the air pollutants sulfur dioxide, nitrogen oxides, peroxyacyl nitrates, and ozone have been considered from chemical, biochemical, and physiological points of view. Physiological observations cannot demonstrate the chemical mode of toxicity. Chemical and in vitro biochemical studies may be irrelevant at the physiological level. Consideration of all three approaches indicates which hypotheses of toxicity are more plausible and suggests new areas of investigation. 

In spite of its long history as a known air pollutant, sulfur dioxide has received little attention from plant physiologists and biochemists. Attempts to assess the physiological relevance of some of the reactions listed in Table I would be appropriate. 

Haider, S.S. 1985. Effects of exhaust pollutant sulfur dioxide on lipid metabolism of guinea pig organs. Ind. Health 23(2) 81—87. 

Haider, S.S., M.Hasan, and N.H.Khan. 1982. Air pollutant sulfur dioxide-induced alterations on the levels of lipids, lipid peroxidation and lipase activity in various regions of the rat brain. Acta Pharmacol Toxicol. 51(l) 45-50. 

The atmosphere is a major source of soil acidity. Even in unpolluted environments rainwater is slightly acidic, having a pH of about 5.7 due to the dissolution of atmospheric CO2 to form the weak carbonic acid (see Worked example 5.4). The CO2 concentration in the partially enclosed soil pore system can be significantly higher (typically up to about 10 times) than in the free atmosphere due to respiration of soil microorganisms and plant roots. This results in a lower pH. In areas affected by industrial pollution, sulfur dioxide and nitrogen oxides dissolve in rainwater to produce sulfuric and nitric acids (acid rain), which are both strong acids and cause even more acidity. 

A few years ago the World Health Organization came to much less uncertainty when stating the toxicity of the most important air pollutants in more general terms and proposing the corresponding noxious concentrations and subsequent air quality standards (WHO, 1972). The way followed in this case has been much less mathematic and more length,y but the consensus arrived at by various sets of experts on SO2 effects can be considered unanimous, even if did not consider in detail sulfate deposition and sulfate aerosol secondary toxicity generated by the primary pollutant sulfur dioxide. 

A limited amount of work has been carried out on the effect of pollutants. Sulfur dioxide decreased the amount of iodine liberated from all reagents the difference between reagents II and III was small. Nitrogen dioxide yielded 8 to 11% interference with reagent III, and about the same with II. Five tests with 500 p.p.m. of nitric acid vapor showed an average interference of 0.5 p.p.m. of ozone with reagent III. Interferences from other smog constituents have not been completely evaluated. 

The air pollutant sulfur dioxide can be partially removed from stack gases in industrial processes and converted to sulfur trioxide, the acid anhydride of commercially important sulfuric acid. Write the equation for the reaction, using the smallest whole-number coefficients. Calculate the value of the equilibrium constant for this reaction at 25°C, from values of AGf in Appendix K. 

We must be able to hold a range of scenarios with regard to each possible application. Advanced fossil-fuel technologies, especially coal-based ones, must be able to meet increasingly stringent environmental requirements for critical air pollutants (sulfur dioxide, oxides of nitrogen), as well as other environmental issues (such as liquid and solid waste), and still remain cost competitive with other fossil fuels, especially natural gas [73]. 

Sulfur, S 32.064 6 Brittle, generally yeUow nonmetal. Essential nutrient for plants and animals, occurring in amino acids. Used to manufacture sulfuric acid. Present in pollutant sulfur dioxide, SOj... 

As an example of how to balance a chemical equation, consider the reaction of hydrogen sulfide gas (H2S) with sulfur dioxide (SO2) to yield elemental sulfur (S) and water (H2O). This reaction is the basis of the Claus process by which commercially valuable elemental sulfur is recovered from pollutant sulfur dioxide and from toxic hydrogen sulfide in sour natural gas. The steps used in balancing the equation are the following ... 

Diesel and Fuel Oils. The second most important petroleum products, which account for about 26 percent of crude oil, are diesel and other fuel oils. These fuel oils have longer hydrocarbon chains than gasoline and thus boil at higher temperatures. Diesel is used as fuel for trucks, buses, ships, locomotives, and automobiles. In Europe, diesel engines are very popular for automobiles as they are more fuel efficient. Environmentalists have expressed concern about burning these fuels because the process creates the pollutant sulfur dioxide. 

Section 18.4 In the troposphere the chemistry of trace atmospheric components is of major importance. Many of these minor components are pollutants. Sulfur dioxide is one of the more noxious and prevalent examples. It is oxidized in air to form sulfur trioxide, which, upon dissolving in water, forms sulfuric acid. The oxides of sulfur are major contributors to acid rain. One method of preventing... 

Such a concern was unheard of before the Industrial Revolution, but today the purity of rainfall is a major concern for many people, especially with regard to its acidity. Most rainfall is slightly acidic because of decomposing organic matter, the movement of the sea, and volcanic eruptions, but the principal factor is atmospheric carbon dioxide, which causes carbonic acid to form. Acid rain (pH <5.6) is produced by the conversion of the primary pollutants sulfur dioxide and nitrogen oxides to sulfuric acid and nitric acid, respechvely. These processes are complex, depending on the physical dispersion processes and the rates of the chemical conversions. 

The following graph shows the concentration of an atmospheric pollutant, sulfur dioxide, for the period 1990-2006. Sulfur dioxide, a product of fossil fuel combustion, is a main precursor to acid rain. In recent years, because of mandatory reductions legislated by the 9-... 

FIGU RE 1.1 Illustration of the definition of environmental chemistry exemplified by the life cycle of a typical pollutant, sulfur dioxide. Sulfur present in fuel, almost always coal, is oxidized to gaseous sulfur dioxide, which is emitted to the atmosphere with stack gas. Sulfur dioxide is an air pollutant that may affect human respiration and may be phytotoxic (toxic to plants). Of greater importance is the oxidation of sulfur dioxide in the atmosphere to sulfuric acid, the main ingredient of acid rain. Acidic precipitation may adversely affect plants, materials, and water, where excessive acidity may kill fish. Eventually, the sulfuric acid or sulfate salts end up in water or in soil. 

The most common source of pollutant acid in water is acid mine drainage. The sulfuric acid in such drainage arises from the microbial oxidation of pyrite or other sulfide minerals as described in Section 3.5. The values of pH encountered in acid-polluted water may fall below 3, a condition deadly to most forms of aquatic life except the culprit bacteria mediating the pyrite and iron(II) oxidation, which thrive under very low pH conditions. Industrial wastes frequently have the potential to contribute strong acid to water. Sulfuric acid produced by the air oxidation of pollutant sulfur dioxide (see Chapter 7) enters natural waters as acidic rainfall. In cases where the water does not have contact with a basic mineral, such as limestone, the water pH may become dangerously low. This condition occurs in some Canadian and Scandinavian lakes, for example. 

At our level in the troposphere, air is a mixture of gases of uniform composition, except for water vapor, which composes l%-3% of the atmosphere by volume, and some of the trace gases, such as pollutant sulfur dioxide. On a dry basis, air is 78.1% (by volume) N2, 21.0% O2, 0.9% argon, and 0.04% carbon dioxide. Trace gases at levels below 0.002% in air include ammonia, carbon monoxide, helium, hydrogen, krypton, methane, neon, nitrogen dioxide, nitrous oxide, ozone, sulfur dioxide, and xenon. 

Movement of air pollutants from one place to another, such as the movement of air pollutant sulfur dioxide from the U.S. Ohio River valley to New England and southern Canada, where it forms acid rain. 

Atmospheric particles may consist of organic or inorganic materials or mixtures of both. Solid pollutant particles include very small combustion nuclei residues from fuel combustion, cement dust, silica dust from sandblasting, and soil dust mobilized by cultivation practices. Sulfuric acid droplets produced by oxidation of pollutant sulfur dioxide in the atmosphere are the most common kind of pollutant liquid droplets. Many kinds of particles are of biological origin and can be considered pollutants when they contribute to respiratory problems. These include bacteria, bacterial spores, fungal spores, and pollen. 

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