Figure 1
(http://www.epa.gov/airmarkets/acidrain)
2.2 How to Measure Acid Rain?
Acid rain is measured using a scale called "pH". The lower a substance's pH is, the more acidic it is. Normal rain is slightly acidic because carbon dioxide dissolves into it, resulting in a pH of approximately 5.5 while pure water has a pH of 7.0. (Elsom,1987:p34)
3. Causes of Acid rain
3.1 History of Acid rain
During the 1970s many countries started to notice changes in fish populations in lakes and damages to certain trees. It was found that the high acidity levels in the lakes, rivers, bays and streams caused it. Acid rain was identified to be the major cause of the changes and the damages in those environments. The USA, Germany, Czechoslovakia, Netherlands, Switzerland and Australia are countries that have been affected by acid rain, however, it has also become a problem for Japan, China and Southeast Asia.
“Ph is measured from Zero to fourteen. On the alkaline side, seawater is around 8 and at the acidic end Orange juice and soft drinks are around PH2 or 3. Unpolluted rainwater should measure at around PH 5 and any measurement under 5 would be considered Acid Rain. As Australia is sparsely populated, its cities are far apart and it has no neighbors, the readings are not very high. In areas where there are smelters and power stations however, the problem of acid rain is far greater. The major effects are on forests and rivers and lakes, where the acid rain causes the soil or water to be so acidified that trees won't grow or in fact they can even die completely and rivers and lakes they can become so acidic that they won't support any sort of aquatic life” (Bubenick, 1984)
3.2 Causes of Acid rain
Cars and trucks are the main sources for the nitric acid that develops into acid rain. Power generating plants, industrial, commercial and residential fuel combustion together contributes to most of the rest in the air. The sulphur dioxide and nitrogen oxides can be transformed into sulphuric acid and nitric acid, air currents can send them thousands of kilometres from the source. When the acids fall to the earth in any form it will have large impact on the growth or the preservation of certain wildlife. Also it might be capable of causing cancer, birth defects, or genetic imbalances for both humans and animals (Bown.1990.p:72)
Also these are emitted primarily from utility and also burning wood. Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid.
The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms. When that happens, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone. It contains an unnatural acidic. This acidic is not to be confused with uncontaminated rain that falls, for that rain is naturally slightly acidic. The acid in the acid rain comes from two kinds of air pollutants, sulphur dioxide (SO2) and nitrogen oxide (NO x). About 2/3 of all SO2 and 1/4 of all NOx comes from electric power generation that relies on burning fossil fuels like coal. (Elsom, 1987:92).
4.Effects of Acid Rain
4.1 Water (or fish)
Acid rain in water can affect the fish in two ways: directly and indirectly. Sulfuric acid directly interferes with the fish's ability to take in salt, oxygen and nutrients crucial for daily life. Osmoregulation is the process of maintaining the delicate balance of salts and minerals in their tissues. For freshwater fish, maintaining osmoregulation is the key to their survival. Acid molecules, which are a result of acid rain in the water, cause mucus to form in the fish’s gills. This in return prevents the fish from absorbing oxygen. If the fish are unable to absorb oxygen, the consequence could be the eventual suffocation of fish and the low pH could throw off the balance of salts in the fish tissue, salt such as the calcium (Ca+2. This can result in poor reproduction. The fish’s eggs produced would be damaged, they could either be too brittle or too weak. The decreased Ca+2 levels also result in weak spines and deformities. Acid Rain has a detrimental effect when it come to the life of fish, although when nitrogen-containing fertilizers are washed off into the lakes, the nitrogen stimulates the growth of algae, which logically would indicate an increase in oxygen production, thus benefiting the fish. However, because of the increase in deaths in the fish population due to acid rain, the decomposition process uses up a lot of the oxygen, which leaves less for the surviving fish to take in. (Elliot .1984: 156)
4.2 soil
Other issues impacted by acid rain are forests and soil. When acid rain falls onto the earth's surface it causes a large amount of damage. The soil is robbed of some vital things. Aluminum that is always present in the soil is freed, and the roots of trees absorb the toxic element. The trees in turn are starved and deprived of vital nutrients such as calcium and magnesium. The Sulfuric acid then returns to earth, when this happens, it clogs up the stomata in the leaves, stopping photosynthesis. In addition, severe frosts may also further aggravate this situation. With sulfur dioxide, ammonia and ozone present in the air, the frost-hardiness of trees are reduced. Ammonia mixes with sulfur dioxide and forms ammonium sulfate. This product forms on the surface of the trees. When ammonium sulfate reaches the soils, it reacts to create both sulfuric and nitric acid. Such conditions also stimulate the growth of fungi and pests like the ambrosia beetle. When trees are under such stress, they release chemicals such as terpenes, which attract the ambrosia beetle, which is a serious killer for forests.
4.3 Plant
It also harms vegetation; acid rain damages the protective waxy coat of leaves. This will interrupt the evaporation of water and air exchange cycle, so the plants can no longer breath leading to a termination of plant growth. Toxic metals are further harmful to human health and high lead levels may harm people who drink the acidic water. Acid rain, acid fog and acid vapour damages the surface of leaves and needles, reducing a tree’s ability to withstand cold temperature, inhibit plant germination and reproduction. It can scar the leaves of hardwood forest, wither ferns and lichens, accelerate the death of coniferous needles, sterilize seeds, and also weaken the forests to a state that is vulnerable to disease infestation and decay. Consequently, tree vitality and regenerative capability is reduced. All this will destroy all the vegetation on the earth. As a result, there will no longer be a source of food for human beings to survive on this planet.
4.4 atmosphere
Acid rain also affects the atmosphere. The effects on the atmosphere are mostly due to dry deposition that was mentioned earlier. The floating particles can contribute to haze, which effects visibility. This makes navigation especially difficult for air pilots. The acid haze also inhibits the flow of sunlight from the sun to the earth and back. Acid rain also affects architecture. Architecture is affected by both dry precipitation and wet precipitation. When these particles land on buildings they eat into the concrete eventually destroying them. This is a potential danger because the infrastructure of the buildings can be destroyed, thus hurting people occupying the building. The SO2 and NO2 emissions add to respiratory problems such as asthma, dry coughs, headaches, and eye, nose and throat irritations.
5. What Society Can Do About Acid Deposition?
5.1 Understanding acid deposition's causes and effects
To solve the acid rain problem, people need to understand how acid rain causes damage to the environment. They also need to understand what changes could be made to the Acid rain sources that cause the problem. The answers to these questions help leaders make better decisions about how to control air pollution and therefore how to reduce - or even eliminate - acid rain. Since there are many solutions to the acid rain problem, leaders have a choice of which options or combination of options are best. As individuals people should invest in energy-efficient appliances, avoid the use of air conditioners, turn off the heater in the evenings, if they have a pool cover it when it’s not in use, also ride a bike or take a bus when traveling. If every one were to apply these practices to there every day lives we could reduce the risk of acid rain becoming out of our control. As a society we can also help by using alternative energy sources. The next section describes some of the steps that can be taken to reduce, or even eliminate, the acid deposition problem
5.2 Clean up smokestacks and exhaust pipes
Almost all of the electricity that powers modern life comes from burning fossil fuels such as; coal, natural gases, and oil. Two pollutants that are released into the atmosphere, or emitted cause acid deposition, when these fuels are burned it creates sulfur dioxide (SO2) and nitrogen oxides (NOx). There are several options for reducing SO2 emissions, including using coal containing less sulphur, washing the coal, and using devices called scrubbers to chemically remove the SO2 from the gases leaving the smokestack. Power plants can also switch fuels; for example burning natural gas creates less SO2 than burning coal. Certain approaches will also have additional benefits of reducing other pollutants such as mercury and carbon dioxide. Understanding these "co-benefits" has become important in seeking cost-effective air pollution reduction strategies. Finally, power plants can use technologies that don't burn fossil fuels. Each of these options has its own costs and benefits, however; there is no single universal solution. Similar to scrubbers on power plants, catalytic converters reduce NOx emissions from cars. These devices have been required for over twenty years, and it is important to keep them working properly and tailpipe restrictions have been tightened recently. (Bown, 1990:152)
5.3 Use alternative energy sources
There are other sources of electricity besides fossil fuels. They include: nuclear power, hydropower, wind energy, geothermal energy, and solar energy. Of these, nuclear and hydropower are used most widely; wind, solar, and geothermal energy have not yet been harnessed on a large scale in Australia.
There are also alternative energies available to power automobiles, including natural gas powered vehicles, battery-powered cars, fuel cells, and combinations of alternative and powered gasoline vechiles.
All sources of energy have environmental costs as well as benefits. Some types of energy are more expensive to produce than others, which means that not all people can afford all types of energy. Nuclear power, hydropower, and coal are the cheapest forms today, but changes in technologies and environmental regulations may shift that in the future. All of these factors must be weighed when deciding which energy source to use today and which to invest in for tomorrow
In summary Acid rain is a huge environmental concern. It causes damages to our lakes, our rivers, our wild life and most importantly human life. Acid rain is absorbed in fruits, and in the tissues of animals. Although these toxic metals do not directly affect the animals, they have serious affects on humans when they are being consumed. . It also causes other problems, such as the release of aluminium and lead into our water supplies causing suffering to human life. Acid rain is a real threat for human beings and the environment. In many countries they have set different procedures to prevent acid rain and even as individuals it’s still possible to fight acid rain. The amount of pollution released must be reduced. However it will take time; even if the pollution were to be stopped today the problem would not end for years to come because of the build up in the soil.
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