SO2 pollution

Reduction of metal oxides with hydrogen is of interest in the metals refining industry (94,95) (see Metallurgy). Hydrogen is also used to reduce sulfites to sulfides in one step in the removal of SO2 pollutants (see Airpollution) (96). Hydrogen reacts directiy with SO2 under catalytic conditions to produce elemental sulfur and H2S (97—98). Under certain conditions, hydrogen reacts with nitric oxide, an atmospheric poUutant and contributor to photochemical smog, to produce N2 ... 

Effects of SO2 pollution in London dramatically described to Charles 0 by John Evelyn (p. 698). 

Sulphur oxides These (SO2 is the most frequently encountered oxide) are powerful stimulators of atmospheric corrosion, and for steel and particularly zinc the correlation between the level of SO2 pollution and corrosion rates is good However, in severe marine environments, notably in the case of zinc, the chloride contamination may have a higher correlation coefficient than SO2. 

Weather conditions at the time of initial exposure of zinc and steel have a large influence on the protective nature of the initial corrosion products This can still be detected some months after initial exposure. Finally, rust on steel contains a proportion of ferrous sulphate which increases with increase in SO2 pollution of the atmosphere. The effect of this on corrosion rate is so strong that mild steel transferred from an industrial atmosphere to a rural one corrodes for some months as though it was still exposed to the industrial environment. ... 

Hi) Poly amines. In many respects the role of poly amines in plant functioning is still mysterious after many years work. They are almost certainly involved in the control of growth and development through their interactions with nucleic acids and membranes (Smith, 1985). There is increasing circumstantial evidence for their involvement, especially of putrescine, in plant responses to a wide range of stresses including pH, Mg deficiency, osmotic shock, cold, SO2 pollution, and cadmium and ammonium toxicity (Smith, 1985). It remains to be determined, however, how, and indeed whether, putrescine accumulation in response to these diverse stresses is beneficial. 

The combustion products from sulfur Impurities In coal are particularly damaging to the environment. In humans, prolonged exposure to sulfur dioxide diminishes lung capacity and aggravates respiratory problems such as asthma, bronchitis, and emphysema. Concentrations as low as 0.15 ppm can incapacitate persons with these diseases, and at about 5 ppm everyone experiences breathing difficulties. In 1952 a particularly serious episode of SO2 pollution In London caused approximately 4000 deaths over several days. 

CuS (. ) -I- 8N03 (f2 7) -I-8H3 0 ag) 8NO(g) -1-3 Cu (c2(7) + iSOn gg) + I2H2 0(/) Taking into account the cost of SO2 pollution of the atmosphere, these more elaborate aqueous separation procedures are economically competitive with conversion by roasting. 

Sulfur dioxide emissions, 23 666-667 Sulfur dioxide gas, 23 774 generation of, 23 771-773 production of, 23 659 Sulfur dioxide gas stream, 23 769 Sulfur dioxide vapor, inhalation of, 23 665 Sulfur dyes, 9 181-182, 242, 262-263. See also SO2 pollution... 

Galvez, N. Barr6n,V. Torrent,. J. (1999 a) Effect of phosphate on the crystallization of hematite, goethite, and lepidocrodte from ferrihydrite. Clays Clay Miner. 47 304-311 Gancedo, J.R. Grada, M. Marco, J.F. Pala-dos, J. (1988) Comparative Mossbauer and SEM study of the corrosion reaction of iron and weathering steel in SO2 polluted atmospheres. Hyperfine Interactions 41 637-640... 

Evelyn describes the effects of SO2 pollution in London to Charles 11... 

Forest damage was also discovered soon after (if we exclude the first observations of Guderian in Germany in 1962) in many other places in continental Europe. The similarity of effects lead some scientists to infer a similarity in causes but the lack of proof is evident forest damage in Europe was thus attributed successively to SO2 pollution, NO2, NO2-SO2 combination, heavy metals and acidity pollution, dryness, frost, disease, lead present in exhaust gases, etc. I would also suggest the intermediate compounds resulting from the photochemistry of naturally... 

There are two ways to minimize the effects of SO2 pollution. The most direct approach is to remove sulfur from fossil fuels before combustion, but this is technologically difficult to accomplish. A cheaper but less efficient way is to remove SO2 as it is formed. For example, in one process powdered limestone is injected into the power plant boiler or furnace along with coal (Figure 17.23). At high temperatures the following decomposition occurs ... 

The range of the Acid Rain Control Areas and the SO2 Pollution Control Areas, as shown in Figure 10, is about 1.09 million km, and comprises 11.4% of the area of China. 

The Acid Rain Control Area involves 14 provinces/autonomous regions/munici-palities south to the Changjiang (Yangtze) River, with an area of 0.806 million km, while the SO2 Pollution Control Area includes 63 cities north to the Changjiang (Yangtze) River, with a total area of 0.29 million km. The Acid Rain Control Area and the SO2 Pollution Control Area comprise 8.4% and 3% of the Chinese land respectively. 

In 1995, the SO2 emission in all of China was about 23.7 million tons, 14 million tons (on about 6090) of which were in the Control Areas. Thus, the acid rain and SO2 pollution control in China will not deteriorate if the SO2 emission is well controlled in these areas. 

Figure 10. Sketch map of the acid control area and SO2 pollution control areas in China (Hao et al, 1998).

The elevated SO2 pollution into the atmosphere and accumulation of HM in the ecosystem provide synergetic environmental impacts (in particular, on soils around the power plant). These impacts result in acceleration of the biogeochemical migration of most HM under acid conditions caused by the SO2 emission from different industrial sectors, including power production. As a negative result, the acidification of tropical soils due to sulfur acidity undoubtedly facilitates the accumulation of a large number of HM in food chains of both terrestrial and aquatic ecosystems (Bashkin Park,... 

The direct impact of anthropogenic air pollutants on the needles and leaves of plants may cause a variety of damage. High average loads and especially extreme load pikes of SO2 in the winter months, lead to characteristic damage symptoms in the case of spruce. The relative tolerance of trees to SO2 pollution is an intrinsic factor of morphological and physiological defense mech-... 

Passive biomonitoring was applied to estimate the air quality in the La Spezia district, Italy, with regard to a coal-fired power plant and other industrial activities (Nimis et al., 1990). The lichen Parmelia caperata collected from Olea sativa trees was meant to biomonitor the SO2 pollution in the study area. The method, adopted by Nimis et al., was designed to avoid subjectivity, to begin with the strategy of sampling and end with the analysis of data. The applied index, based on frequency of species... 

Combu.stion of coal accounts for about 65% of the SO2 released annually in the United States, and combustion of oil accounts for another 20%. TThe majority of this amount is from coal-burning electrical power plants, which generate about 50% of our electricity. The extent to which SO2 emissions are a problem when coal is burned depends on the amount of sulfur in the coal. Because of concern about SO2 pollution, low-sulfur coal is in greater demand and is thus more expensive. Much of the coal from east of the Mississippi is relatively high in sulfur content, up to 6% by mass. Much of the coal from the western states has a lower sulfur content, but also a lower heat content per unit mass, so the difference in sulfur content per unit of heat produced is not as large as is often assumed. 

Because acids react with metals and with carbonates, add rain is corrosive both to metals and to stone building materials. Marble and limestone, for example, whose major constituent is CaC03, are readily attacked by acid rain ( FIGURE 18.8). Billions of dollars each year are lost because of corrosion due to SO2 pollution. 

Most industrialized countries have problans with their SO2 emissions. Thus, for several decades the interest in research for controlling SO2 pollution has continued, use of ACs being one possible alternative for controlling these emissions [6,60,140-142]. 

Hypersensitivity to the irritant effects of inhaled sulfur dioxide is well recognized and is a usual feature of asthma. As little as 1.0 ppm of the inhaled gas can produce significant broncho-constriction in groups of asthmatics (Koenig et ai, 1980 Koenig et ai, 1982), and the symptomatic severity of asthma can be correlated with atmospheric SO2 pollution (Boushey, 1982). Hypersensitivity appears to be due to an exaggerated reflex response to chemical irritation on the background of the bronchial hyper-reactivity which characterizes the asthmatic state (Boushey, 1982). 

The Blue Ridge Mountain next to Palmerton, Pennsylvania, was decimated by SO2 pollution from the zinc refinery located there. The roasting of the ZnS ore to produce ZnO (used to produce Zn metal] also made SO2 most of which was captured to generate sulfuric acid. But cumulative SO2 releases over many years killed most of the vegetation on the mountain next to the refinery. The refinery is now shut down, and the Environmental Protection Agency (EPA) is doing extensive remediation of the mountain with acid- and zinc-resistant plants. 

---