Atmospheric pollution acid rain

Acid deposition, the deposition of acidic substances from the atmosphere onto Earth s surface, is another phenomenon associated with atmospheric pollution. Acid rain refers to the low pH of precipitation that has been observed in... 

Gao, S., K. Sakamoto, D. Zhao, D. Zhang, X. Dong, S. Hatakeyama Studies on atmospheric pollution, acid rain and emission control for their precursors in Chongqing, China, Water, Air, and Soil Pollut., 130 (2001) 247-252. 

CONTRIBUTION TO FOREST DECLINE STUDIES BIOCHEMICAL EFFECTS OF ATMOSPHERIC POLLUTION (ACID RAIN) IN PICEA TREES... 

Clearcoat 40 pm Withstand solar radiation, atmospheric pollution (acid rain, bird droppings, aggressive chemicals like road salts and caustic detergents)... 

Coal is formed by the decomposition of plants under pressure. Some coals contain 2-6% sulfur. Burning these coals has led to pollution of the atmosphere and acid rain.< When coal is heated in the absence of air, a process called destructive distillation, it yields three products ... 

A characteristic that is analogous to alkalinity is acidity, the capability of species in water to produce H ion or to neutralize OH ion. The most common acidic component of water is dissolved CO2, which produces weakly acidic water. Relatively more acidic water with a low pH generally indicates pollution. Acidity may be due to dissolved hydrated metal ions, such as Fe(H20)g, which readily release H ion. Strong acids including H2SO4 and HCl in water are called free mineral acids. Water containing a substantial concentration of free mineral acid may be quite toxic to most forms of aquatic life. The pollutant acid mine water contains an appreciable concentration of free mineral acid, and free mineral acid may enter bodies of water from the atmosphere as acid rain. 

Selection of pollution control methods is generally based on the need to control ambient air quaUty in order to achieve compliance with standards for critetia pollutants, or, in the case of nonregulated contaminants, to protect human health and vegetation. There are three elements to a pollution problem a source, a receptor affected by the pollutants, and the transport of pollutants from source to receptor. Modification or elimination of any one of these elements can change the nature of a pollution problem. For instance, tall stacks which disperse effluent modify the transport of pollutants and can thus reduce nearby SO2 deposition from sulfur-containing fossil fuel combustion. Although better dispersion aloft can solve a local problem, if done from numerous sources it can unfortunately cause a regional one, such as the acid rain now evident in the northeastern United States and Canada (see Atmospheric models). References 3—15 discuss atmospheric dilution as a control measure. The better approach, however, is to control emissions at the source. 

See also Acid Rain Agriculture Air Pollution Atmosphere Biological Energy Use, Cellular Processes of Climatic Effects Environmental Problems and Energy Use Green Energy Tlierniodynaniics. 

See also Acid Rain Air Pollution Atmosphere Environmental Problems and Energy Use Ocean Energy Systems Pollution and Energy Efficiency. 

Constant dripping of rain water contaminated by atmospheric pollution (e.g. from near-by chimney stacks) or by organic acids from lichens, etc. 

Rain in equilibrium with atmospheric C02, but uncontaminated by industrial emissions, should have a pH of 5.7. However, atmospheric pollution from burning fossil fuels has resulted in acid rain of pH as low as 3.5 (24). If this condition continues for a long time, it may lead to a change in groundwater composition, which may considerably change the migration of plutonium in nature. 

Rain unaffected by human activity contains mostly weak acids and has a pH of 5.7. The primary acid present is carbonic acid, H2C03, a weak acid that results when atmospheric carbon dioxide dissolves in water. The major pollutants in acid rain are strong acids that arise from human activities. Atmospheric nitrogen and oxygen can react to form NO, but the endothermic reaction is spontaneous only at the high temperatures of automobile internal combustion engines and electrical power stations ... 

Acid deposition has been known to exist since early in the industrial age. The principle pollutants responsible for the elevated levels of acidity are the oxidized forms of sulphur and nitrogen that have been emitted as by-products from non-ferrous smelters, fossil-fueled power generating stations, and motor vehicles. The pollutants are transported substantial distances from the source areas by the atmosphere. They are deposited on receptor regions remote from the sources as acidic rain, snow, and fog or as gasses and dry particulates. 

Acid rain. Natural (unpolluted) precipitation is naturally acidic with a pH often in the range of 5 to 6 caused by carbonic acid from dissolved carbon dioxide and sulfurous and sulfuric acids from natural emissions of SO and H2S. Human activity can reduce the pH very significantly down to the range 2 to 4 in extreme cases, mainly caused by emissions of oxides of sulfur. Because atmospheric pollution and clouds travel over long distances, acid rain is not a local problem. The problem may manifest itself a long way from the source. Problems associated with acid rain include ... 

The manufacture of fine chemicals and pharmaceuticals generates in the order of 25-100 times more waste than product [52], Inorganic salts account for the bulk of the waste and are most often produced by neutralization of acidic or basic solutions [53]. Salts can pollute soil and ground water, lower the pH of atmospheric moisture and they may contribute to acid dew or acid rain [6]. For cleaner production, their minimization is essential and hence our concentration on new processes, such as the etherification (discussed in Sect. 2.6.3.1) and hydrogen transfer reduction (Sect. 2.6.3.2), that avoid salt formation and the use of salts. 

At one point it was assumed that the earth, its oceans and rivers, and its atmosphere were so vast or self-cleansing that we could discharge anything into them without damage to our planet. We now know this is not true. Currently, we must deal with toxic waste dumps, with smog, with acid rain that kills forests, and with pollution of rivers and the ocean by chemical discharges. How did this happen ... 

Making a Model Acid precipitation often falls to Earth hundreds of kilometers away from where the pollutant gases enter the atmosphere because the gases diffuse through the air and are carried by the wind. In this lab, you will model the formation of acid rain to observe how the damage caused by acid varies with the distance from the source of pollution. You also will observe another factor that affects the amount of damage caused by acid rain. 

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