Air Pollution Essay
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Acid Rain is the term given to any precipitation that is above normal acidity, this includes snow and fog. The acidity or causticity of a solution is measured in pH. A neutral pH is 7, acidic is lower then 7 and a base is greater than 7. The normal pH of rainwater is 5.5 (slightly acidic). In Scotland on April 20, 1974 the rain measured 2.4 and in West Virginia in 1978 the rain had a pH of 2.0! This was in the 70's and air pollution since then hasn't gotten any better. This very highly acidic rain kills plants and animals and destroys buildings.
Acid rain occurs when the moisture in the air mixes with Carbon, Nitrogen, and Sulphur gases. These gases are released into the air by the burning of fossil fuels (natural gas, coal and oil). The primary source of the gases comes from electric companies that burn coal.
Damage caused by acid rain is tremendous. The acid in the rain bonds with the minerals in the soil, tying them up so that plants can not use them. The plant becomes mineral deficient and weak. The rain also kills the plant's leaves, further weakening it and making the plant more susceptible to fungus and other diseases. This is a major agricultural problem.
The rain effects lakes, rivers and the animals living within them. The plants in the lakes and rivers are killed in the same way as land plants. The fish and other animals are left with no food. The animals that do survive are killed from the metals being drawn into the water from the soil, when the acid bonds to them.
Many architectural structures are destroyed from the acid rain. Most of the cement used to make our buildings.
are made from lime which is very reactive with acid. You can see the effects of this weathering if you look at old gravestones or statues. The words etched in some of the gravestones can barely be read anymore because they are so worn away. Weathering is a natural process. Rain is normally slightly acidic but because of air pollution and the higher acidity of the rain, the process is sped up greatly.
Industry is looking for solutions to the air pollution problem. The best solution would be to stop burning fossil fuels all together but at this time we have no other alternatives. Scientists are trying ways to cut down on pollution. One way is to wash the coal before they burn it. Washing it takes off most of the sulphur but not all of it. The rest would have to be removed chemically but this process is still being researched. The problem with this is what to do with all the excess sulphur. Another solution is to clean the smoke before it is released into the air. Many filters have been installed in smoke stacks but again this solution is not 100% effective.
Another major environmental problem caused by air pollution is global warming or the "greenhouse effect". The greenhouse effect is caused by solar energy being trapped by CO2, Methane, Ozone (O3), Nitrous gas, and Chlorofluorocarbons (CFCs) that are in the air. The solar energy comes into the atmosphere as light, it hits the Earth, looses some of its energy and becomes heat. Because the heat does not have as much energy it can not penetrate back through the blanket of gases. The Earth has a natural greenhouse effect caused by the CO2 in the atmosphere. If we didn't have this natural greenhouse effect, the Earth would be too cold to live on. We have increased this effect through the release of all the gases I have mentioned above.
CO2 is released into the air from factories and from the exhausts of cars. Some of this CO2 in the atmosphere is used when the plants make their food but with many of our forests being cut down it makes our problems worse. CFCs are released into the air from aerosol cans. They are also used in air conditioners and refrigerators and leak from these places. Ozone is created when the sunlight strikes nitrogen oxide from car exhaust and the oxygen from it bonds with oxygen gas. Ozone is a very toxic gas and is good at filtering out UV light in the stratosphere but is bad for us when it is in the lower atmosphere.
Some people may wonder why global warming is bad. Who wouldn't want summer year around? The reason it is bad is because it wouldn't stop at a comfortable warm all year around. The winters would be warm and the summers would be unbearably hot! Some scientists believe that if the trend continues and becomes worse, we will have to abandon the southern areas and keep moving north to escape the heat. Many places will become dry arid dessert. This great warming also brings up the idea of what will happen to all the ice at the poles? With the temperature rising, the ice will melt and sea levels will rise significantly. Most of our costal land is only a few feet above sea level. A rise would flood all of it including most of the state of Florida!
The average yearly temperature has been going up by .5 degrees Celsius. This is much lower than what scientists have predicted and some say that this proves there is no such thing as global warming. The reason for this is that the air pollution surrounding the earth is having two effects. One is the warming and the trapping of the heat in the atmosphere and the other is keeping the heat out. Most of the sunlight is getting in and once it is in it stays in but the pollution is also acting like a shield and deflecting some of the light so it never enters the atmosphere. The prevailing trend, although, will be a warming because not enough light will be deflected.
We can slow down the greenhouse and maybe even stop it by slowing down and stopping the release of the greenhouse gases. One of the ways this is being done is by putting the catalytic converter on cars. The device goes on the exhaust pipe of the car and reduces the amount of CO2 that is released into the atmosphere. Another way is to control the use of CFCs. Aerosol cans are supposed to be banned by the year 2000 and they are working on new coolants for refrigerators and air conditioners. We can also slow down the rate of deforestation and plant more trees.
The last major environmental problem caused by air pollution is ozone depletion. As mentioned before ozone is three oxygen molecules (O3). It is concentrated in the stratosphere about 20-25 km above the earth's surface. Ozone is what protects us from shriveling up under the sun's powerful rays. It blocks out the harmful ultraviolet (UV) light which causes skin cancer. Two major holes have been discovered in the ozone layer: a large one above the south pole and a smaller one above the north pole. These two areas have absolutely no protection from UV light.
CFCs, as mentioned before, are commonly used in aerosol cans, air conditioners, and refrigerators. They do not break down in the lower atmosphere and are carried up into the stratosphere. Ozone is a very unstable molecule and reacts readily with the Chlorine in the CFC compound. When a CFC compound is hit by ultraviolet radiation it frees one of the chlorine atoms. The chlorine reacts with one of the oxygen atoms in an ozone compound forming a chlorine monoxide and oxygen gas (O2). A second reaction then releases the chlorine again so it can react with another ozone molecule. The two poles are where these gases collect because of wind currents and this is why the two holes in the ozone are located there. Another pollutant that is destroying the ozone is Nitrous gas. It is released from jet engine's exhaust. The high flying jets put the pollutants right where they need to be to cause the destruction.
Some of the solutions to help slow the depletion is to use hydro- fluorocarbons (HFCs) instead of CFCs, cutting down on the use of CFCs, and using alternative jet fuel which doesn't release Nitrous gas. Ozone is constantly being created. The reason we have a problem is that it is being destroyed at a much faster rate then it is replenishing itself. All we need to do is slow down the emission of these gases. This will give the ozone time to repair itself. Then we need to keep the emissions low so that this problem will not reoccur.
These problems may seem serious and they are but for right now they are not irreversible. We can do some everyday things that will help the environment. Make sure that you only have lights on in the room you are in. If you turn lights off as you leave a room and don't leave every light in the house on, less electricity has to be produced at Detroit Edison, that means less coal will be burned and less CO2 and the other gases will be produced and released into the air. Another easy way to help is to plant a tree in your yard or to get involved in a tree planting program. Buy pump bottles instead of aerosol cans or you can car pool to school or work. There is no reason why you should have to drive alone when you know about 10 people who are going to the same place you are every single day. Drive slower, this may seem like an odd one but the faster you go the faster your engine works, the more fuel it uses and the more gases that are being put into the air. Just by driving the speed limit or five under you can help to save the environment.