Formation and Effects of Acid Rain - Research Paper Example

Formation and Effects of Acid Rain Abstract The increased urbanization, as well as industrialization, results in emission of large quantities of various gases into the atmosphere. Acid precipitation happens when gases such as sulfur oxides and nitrogen oxides are emitted. These gases accumulate in the atmosphere and fall in different forms. The main sources of these two gases are combustion of fossil fuels and automobile emissions. Additionally, power plants emit both sulfur oxides and nitrogen oxides gases into the atmosphere. Due to increased demand for energy, some countries opt for the combustion of cheaper fossil fuels resulting in buildup of gases in the atmosphere. Acid rain is thus a global concern since it affects the contaminators and the non-polluters. Acid rain falls in different forms that could be wet, precipitation, or solid, and causes destruction of animal and plant life as well as other structure. The formation and effects of acid rain will be discussed in this paper. Introduction Human beings tend to exploit numerous natural resources to produce energy. To obtain cheap energy humans frequently combust fossil fuels such as coal, natural gas, and oil. Burning of these substances is crucial in that it helps to obtain economical energy for different purposes. However, the combusted fuels produce wastes that cause environmental pollution. The main wastes are gases, which accrue in the atmosphere and end up cause atmospheric pollution. Additionally, some of the gases combine to form more detrimental substance that may reach the earth surface in form of acid rain. Acid rain is a terminology used to refer to a substance from the atmosphere, which originates from both natural and manmade sources, and it has remarkably high quantities of sulfuric as well as nitric acid. The nitric and sulfuric acids are mainly from activities such as volcanic eruptions in addition to from human activities stemming from combustion of fossil fuels such as coal. Although natural factors contribute to formation of acid rain, human activities are the main contributors of acid rain. Causes of Acid Rain Like stated above, acid rain is mainly a mixture of sulfuric and nitric acids. The sulfuric acid is formed from degradation sulfur deposits in the environment while nitric acid forms from nitrogen emissions. Robert Angus Smith first used the term acid rain in 1872 to describe a type of rain falling in Manchester in United Kingdom that had high levels of acidity. Acid deposition or precipitation is an alternative term used to describe acid rain. Although enacting Clean Air Act Amendment (CAAA) helped reduce instances of acid precipitation, it did not eradicate this problem completely (Singh & Agrawal, 2008). When some compounds burn, they produce sulfur dioxide, which undergoes oxidation reactions to form sulfuric acid. Nitric acid forms from oxides of nitrogen as wells as from depletion of the ozone layer. The compounds get into the atmosphere when humans combust matters such as combustible wastes and fossil fuels. Additionally, thermal power plants, automobiles, and other machineries combust fuels and emit plenty of gases into the atmosphere. The main source of atmospheric sulfur oxides is volcanic eruptions. Oceans are another source of sulfur oxides. Sulfur oxide can also result from activities such as iron smelting and melting of other metals such as zinc and copper (Singh & Agrawal, 2008; Likens, Driscoll, & Buso, 1996). Nitrogen oxides result from a variety of processes, which include volcanic eruptions, biological processes, and lightening. Additionally, other processes such as operations in power stations, industries, and automobiles emit some oxides. Ordinarily, precipitation is slightly acidic since it reacts with carbon dioxide in the atmosphere forming carbonic acid. Additionally, slight amounts of nitrogen react with rainwater to for nitric acid. However, the acidity is generally negligible and the pH is approximately 5.6. The precipitation is considered acid rain when the acidity is considerably high (Morgan, 2009; Brimblecombe, Hara, Houle, & Novak, 2007) When sulfur and nitrogen oxides react with other compounds in the atmosphere, they become oxidize and form acidic gases. When precipitation passes through the atmosphere, it combines with the above oxides and other compounds and becomes acidified (Brimblecombe, Hara, Houle, & Novak, 2007). For the acid rain to form sulfur dioxide or nitrogen oxides, react with oxygen in presence of sunlight to form mists containing sulfuric or nitric acid. Since the atmospheric temperatures are significantly high, the acids persist in vapor state. However, when the atmospheric temperatures decline, the acids condense and may combine with carbon particle in the atmosphere. In such cases, the deposits fall in form of black particles. When other oxidizing agents in the atmosphere oxidize the acidic gases to form sulfuric and nitric acid, the process entails a number of phases. The oxidants include water, oxygen, and hydroxide ( Singh & Agrawal, 2008). Sulfur may react with oxygen to form sulfur dioxide, which is released into the atmosphere. The sulfur dioxide in the atmosphere is eventually oxidized to form sulfur (IV) oxide that is easily converted to sulfuric acid in presence of a catalyst such as ammonia. Nitric acid is formed by reactions involving nitrogen and oxygen. Nitrogen combines with different numbers of oxygen atoms to form nitrogen oxides, which react with moisture to form nitric acid (Morgan, 2009). Effects of Acid Rain The acid depositions can fall in wet forms such as rain, fog, or snow. Additionally, the deposits can reach the earth surface as gases or particles such as aerosols. Acid rain is considered to be among the most serious causes of environmental problems. When the depositions fall, they may infiltrate into the soil affecting the soil pH hence the life of both plants and animal (Brimblecombe, Hara, Houle, & Novak, 2007). Additionally, they may dissolve in running water and be transported into rivers and other water bodies where the acid destroys the aquatic life. When the acid deposits falls on plant and other structures, it may corrode them causing devastation. When acid rain falls, it deposits acid compounds on the earth surface, which causes effect when they get into plants, soil, surface water, and other forms of vegetation resulting in ecological disasters (Likens, Driscoll, & Buso, 1996; Morgan, 2009). When acidic rain falls, it leaches into the soil and alters the pH of the soil. This has effects on the ability of plants to absorb nutrients from the soil. Acid deposition is known to mobilize aluminum in the soil preventing absorption of calcium by trees. This is because the acid transforms calcium into a form that cannot be absorbed by roots. Acid rain also acidifies the soil resulting in exchange of ion between hydrogen ion and cations such as magnesium, and potassium. The cation formed are easily leached into the soil and become inaccessible to plants. Moreover, the acid depositions remain in the soil for long periods, which affects the growth of the trees resulting in decreased diameter growth. Acid rain has also been shown to interfere with litter decomposition by slowing the decay process particularly of materials with high quantities of cellulose. This reduces the fertility of the soil resulting in retarded growth in plants. Soil acidification can be demonstrated by changes in vegetation growth and distribution. Acid rain deposits may get into water bodies making the water acidic. Although water bodies such as streams, oceans, and s have considerable amount of acids in them, acid precipitation increases the acidity to disturbing levels. Acidity in water bodies results in increased rate of mortality of aquatic animals such as fish, amphibians, and aquatic plants. Additionally, acid water alters the distribution of other organisms such as bacteria and fungi. When acid rain falls on plants and crops, it leads to a number of processes. Plant parts such as leaves may die. Additionally, carbon dioxide fixation is tampered with. Other physiological processes, such as photosynthesis, are interfered with affecting growth of crops. When the morphology of the plant is affected, other processes are also affected. A good example is alteration in stomata conductance due changed pH, and also alterations in leaf morphology. The morphological features of a plant are also distressed. The end and overall result is reduced yields. Acid rain may also fall on other objects such as rocks, stones, and buildings damaging them. Sulfuric acid has been shown to corrode materials such as ferrous metals in addition to causing rusting in metallic materials (Singh & Agrawal, 2008; Morgan, 2009). Acid rain also affects human health. Direct or indirect contact with acid rain has devastating impacts on humans. Indirect contact mainly occurs when human ingest food substances, which have absorbed high quantities of acids. When humans have direct contact with sulfuric and nitric acids, they are affected. The effects may include respiratory problems when acidic moisture is inhaled. Additionally, the acids are toxic and can cause effects such as irritation on the skin and eyes (Morgan, 2009). Conclusion Human activities such as combustion of fossil fuels results in emission of gases into the atmosphere. Sulfur oxides and oxides of nitrogen are among the gases released into the atmosphere. Other than combustion of fuels, the sulfur and nitrogen oxides can result from volcanic eruption, emission from automobiles, while biological process may result in release of nitrogen oxides. The oxides react with oxidants and moisture in the atmosphere to form sulfuric and nitric acid. The two acids dissolved in moisture form acid rain. The acid rain formed is in gaseous form and can be blown by wind to other regions where it eventually falls. When acid rain falls, it gets into the soil and water bodies increasing the acidity. The alterations in pH affect plants and animals resulting in their death or reduced produce. Additionally, the hydrogen ions in the acid precipitation react with cations such as potassium, magnesium, and calcium making them unavailable for plant use. The acid rain also affects human health when inhaled or through contact. References Brimblecombe, P., Hara, H., Houle, D., & Novak, M. (2007). Acid Rain - Deposition to Recovery. New York: Springer. Likens, G., Driscoll, C., & Buso, D. (1996). Long-Term Effects of Acid Rain: Response and Recovery of a Forest Ecosystem. Science, New Series, Vol. 272, No. 5259, 244-246. Morgan, S. (2009). Acid Rain. New York: Sea-To-Sea Publications. Singh , A., & Agrawal, M. (2008). Acid rain and its ecological consequences. Journal of Environmental Biology, Vol 29(1) , 15-24. Read More