Acid rain is also known to play a part in "forest decline." Experimental data collected indicates that "more than 50 percent of the red spruce (in the Adirondacks, the Green Mountains and the White Mountains) have died in the past five years" (Mohnen 32). However, while the relationship between acid rain and groundwater contamination has been experimentally established, the relationship between forest erosion and acid rain is not as clear. In fact, as of 1988, "a firm casual link" had not been established (Mohnen 34).
While the concern about acid rain has arisen since the 1960s, the compounds capable of producing harmful acids have actually been present in the environment for a very long time. Since before the industrial revolution, natural processes like those carried out by volcanoes and soil bacteria, have produced sulfuric and nitric acids and released them into the atmosphere (Mohnen 30). With these pollutants in the air the natural atmospheric reaction is to "wash" itself through waste elimination by precipitation. The process, then, for dumping these toxic acids back to the ground has been around longer than just the industries.
The relationship between acid rain and the rapid deterioration of the environment has been difficult to establish. There is no known way to pinpoint the exact source of pollutants present in a raindrop. For example, a raindrop that falls in Houston may contain sulfuric acid produced in New Jersey. There is no precise way of determining origin.
Sulfur dioxide and nitrous oxide make up a major portion of acid rain. These contaminants are produced mainly as a by-product of electricity generation. Coal is the principle fossil-fuel used in this process and actually "coal causes about half the nation's acid rain" (Cullen 50).
The rapid spread of industry in the 20th century may be responsible for the growing concern after the 1960s. This means that industrial pollution is the determining factor for the presence of acid rain. Even the space shuttle program has been criticized. The space shuttle's solid rocket boosters are suspected of contributing to pollution of the atmosphere. Tests now conducted twice a year produce 109,000 kg of hydrochloric acid and 170,000 kg of aluminum oxide during each test. NASA responds by saying that these compounds are diluted to safe levels by the wind (Fulmer 7). This response, however, does not account for where those compounds relocate.
The increased presence of these dangerous compounds in the atmosphere and their harmful effects on the environment has sparked a great deal of interest and concern about the sources of these toxic pollutants and solutions for disposing of and eliminating these dangerous compounds from our environment.
In recent years, government and industry have made efforts to present a solution to the acid rain problem which is both effective in removing the contaminants and cost-effective. Most recently, President Clinton presented a proposal for a Btu tax, a tax which basically made it costly for consumers to use coal as an energy source. This proposal was rejected, though, because it would be difficult to persuade the public to pay those taxes (Cullen 52).
During the Reagan administration, lack of government cooperation made it difficult to support any reasonable solution for acid rain that was available at that time. The Department of Energy (DOE) and the Environmental Protection Agency (EPA) were involved in a great dispute where the DOE was accused of manipulating information for its own benefit, or in other words, increased funding from Congress. According to the EPA, the DOE allegedly doubled the cost of pollution control. The DOE also faced accusations of ignoring "cheaper construction alternatives" (Melamed 37).
It has been under these conditions that research into a solution to acid rain has been conducted. In spite of the controversial nature of this issue and the emotional responses it can generate, several solutions have been proposed to deal with the emission of contaminants into the environment.
Although science is not yet sophisticated enough to determine pollutant origin or acid rain's effect on forest decline, it is evident that solutions are needed for drastically reducing if not eliminating acid rain to protect our water resources, our forests and our soil.
One possible solution is based on the principle of emission reduction from power plants which utilize fossil fuels (Mohnen 36). This principle serves as the foundation for solving the problem because the growth of industry suggests that consumption of fossil fuels is likely to increase. Also, conversion of energy sources to alternatives like natural gas is slow in coming.
The solution that is gaining a lot of support involves the combination of coal with flue-gas desulfurization (FGD). This process involves washing coal exhaust gases with wet limestone. In application, FGD has achieved some success. The outcome, however, has been lowered efficiency of the power plant and ineffectiveness of reducing production of nitrogen oxides. (Mohnen 36-37) Long term effects, though, could be the reduction of sulfur emissions by more than 80 percent but these long term projections for emission reduction could extend over the course of about 30 years. In this time more damage, possibly irreversible, could be done to the environment. FGD needs to be made available immediately rather than over a long period of time to try and minimize the damage that could be done.
Regarding the question of efficiency, when FGD is combined with a spray of calcium carbonates and magnesium carbonates, the absorption of sulfur dioxide is maximal. Acetone, a by-product of this new process, reacts with nitrogen oxide to produce harmless nitrogen and gypsum. Currently, the high cost of acetone appears to be the only significant drawback (Business Weekly 76).
Building new plants equipped with this technology would be costly and time consuming. However, time has worked in favor of those who support FGD as a means to combat emissions release and acid rain. Many coal-burning plants are due to be refurbished. This presents a great opportunity to fit these plants with the equipment to clean up their act. Also, it is much easier to refurbish existing plants than to gain government approvals for building new plants (Mohnen 37).
Ultimately, the government must have a say in dealing with emissions control. Congressional leaders in 1988, the deciding factors regarding funding, favored the short term capabilities of FGD. By 1988, the Department of Energy had set aside 5 million dollars to further develop FGD and the EPA continued to sponsor research on FGD. Overall, this shows approval from the U.S government for FGD as an immediate effective solution for dealing with the causes of acid rain.
FGD is by no means the only solution for dealing with the causes of acid rain. Many other procedures have shown themselves to be very promising. One example, which is similar to FGD, is very promising because it involves the removal of sulfur dioxide and nitrogen oxide using a single phosphate/alkali emulsion. The products of this process can even be used as fertilizer (Chang/Liu 151). Because this procedure is still in its experimental stages, it is unlikely to appear in industry until more testing is done. Also, the financial consideration is left to be studied.
Acid rain is caused by natural forces as well as by man and industry. Although nature's role in creating acid rain has always been present, recent technological advances have added to the process. The atmosphere has been forced to "wash" out more and more waste and dump it on our environment. Luckily, scientists have been able to come up with several solutions to deal with the sources of the acidic compounds in acid rain. FGD, flue-gas desulfurization, has become the leading hope in dealing with emissions release. It is continuously becoming more efficient. The efforts to deal with acid rain certainly do not end with FGD. Solutions for this serious environmental crisis must be found and introduced as quickly as possible in order to ensure that our environment is relieved of the burden of our waste.
"This Popcorn Can Stop Acid Rain Before It Starts." Business Weekly 18 July 1994: 76
Chang, S.G., D.K. Liu. "Removal of Nitrogen and Sulfur OxidesFrom Waste Gas Using a Phosphorus/alkali Emulsion." Nature 11 January 1990: 151-153.
Cullen, Robert. "The True Cost of Coal." Atlantic Dec 1993: 38-52
Fulmer, Douglas. "Launching Dirty?" Ad Astra Sept. 1991: 6-11
Melamed, Dennis. "Clean Coal Fuels Row Over Acid Rain." New Scientist 14 April 1988: 37
Mohnen, Volker A. "The Challenge of Acid Rain." Scientific American Aug. 1988: 30-38
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