Acid Rain. The term "acid rain" is commonly used to mean the deposition of acidic

Transcription

1 Amy Flaherty October 3, 2003 Environmental Hazards Acid Rain The term "acid rain" is commonly used to mean the deposition of acidic components in rain, snow, fog, dew, or dry particles (pubs.usgs.gov). Acid rain has been a recognized problem since the early 70 s that affects major areas of North America and Europe. This is because this areas are highly industrialized and the burning of fossil fuels, commonly used in these areas, are released into the atmosphere. Acid rain effects the local natural environment and some man made products. Many programs are in effect to try to cut down on the chemicals used in these factories. Sulfur and nitrogen are the two main elements that are responsible for the composition of acid rain. Sulfur is released from the burning of coal and oil. Once in the air it joins up with oxygen molecules and forms sulfur dioxide. Sulfur dioxide does not react with very few chemicals in the atmosphere, this allows it to travel very long distances. Once it reaches the ozone it can turn into sulfur trioxide, which when it dissolves in water forms a diluted solution of sulfuric acid. Nitrogen makes up about 78% of the atmosphere ( When nitrogen is heated at high temperatures in factories, it can combine with oxygen from the air to form nitrogen oxide and nitrogen dioxide. Sunlight increases the rate of most of these reactions. If dissolved in water it makes a weak form of nitric and nitrous acids. Although natural sources of sulfur oxides and nitrogen oxides do exist, more than 90% of the sulfur and 95% of the nitrogen emissions

2 occurring in eastern North America are of human origin. Naturally occurring sulfur and nitrogen are released from volcanoes, lightning, forest fires and biological decay. Actual amounts released from natural sources in the world are difficult to quantify; in 1983 the United Nations Environment Program estimated a figure of between 80 million and 288 million tons of sulfur oxides per year (compared to around 69 million tons from human sources world-wide). Natural sources of nitrogen oxides include volcanoes, oceans, biological decay and lightning strikes. Estimates range between 20 million and 90 million tons per year nitrogen oxides released from natural sources (compared to around 24 million tons from human sources worldwide) ( Rain is naturally acidic, the way rain is measured for acidity is through a scale called the ph. The ph scale measures how acidic or basic a substance is. It ranges from 0 to 14. A ph of 7 is neutral. A ph less than 7 is acidic, and a ph greater than 7 is basic. ( A change in one unit of the ph scale is a tenfold change in the concentration of acidity. When rain has a ph of less than 5.3 it is considered acid rain. In 1977 the need to investigate and measure acid rain so the National Atmospheric Deposition Program (NADP). There are around 220 stations set up around the United States to collect samples. The EPA also has programs to monitor SO2 and NO2 in the air. These program are not intended to consider acid rain, however they do give scientist an idea of the amount of these chemicals in the air in certain locations. Acid rain affects many factors of the environment; the most obvious is the effect of fish in acid sensitive lakes and rivers. The acidic water kills of many fish,

3 plants and other aquatic animals. In forest acid rain removes many vital nutrients from the soil. It also weakens the natural defense of trees, making them more susceptible to diseases and pest. Slower growth, injury, loses of leaves or needles, and death of trees is caused by acid rain. Nitrates are deposited from acid rain. Too much nitrogen can cause an over nourishment in areas where rivers meet oceans. This can cause on over growth of algae and other bothersome plants. It is thought that s around 40% of the total nitrogen flowing into The Atlantic and Gulf Coasts is caused from acid rain. The effect of acid rain directly on human health is not known. It is perfectly safe for people to walk in acid rain or swim in lakes affected by acid rain. The sulfur dioxide and nitrogen oxides in the atmosphere are a bigger concern to human health. This is because the sulfur dioxide and nitrogen oxides can form into sulfate and nitrate particles which people can inhale. These particles may cause asthma and bronchitis which can lead to early death from these heart and lung disorders. These sulfate and nitrate particles in the atmosphere also cut down on the visibility of the air. Sulfate particles account for 50 to 70 percent of the visibility reduction in the eastern part of the United States ( Acid rain does not only damage the natural ecosystems, but also man-made materials and structures. Marble, limestone, and sandstone can easily be dissolved by acid rain. Metals, paints, textiles, and ceramic can effortlessly be corroded. Man-made materials slowly deteriorate even when exposed to unpolluted rain, but acid rain helps speed up the process. Acid rain causes carvings and monuments in stones to lose their features.

4 Many actions are being done to help reduce acid rain, international, nationally and locally. Since the chemicals that cause acid rain can travel hundreds of miles in the atmosphere, many international programs have been developed to counteract this problem. The first international group to recognize these problems was called the United Nations Economic Commission for Europe (UNECE) and was organized in In 1985 country members of UNECE agreed to the Protocol on the Reduction of Sulphur Emissions. This program was to reduce sulfur dioxide emissions by 30% by 1993, which was accomplished in the time frame. A second protocol was signed in 1994 agreeing to reduce sulfur emissions by 70%-80% by Sulfur emissions in Europe have fallen by 25%- 30% from and by another 40% by 2000 ( To reduce nitrogen oxide the Sofia Protocol was made in 1988 for European countries. This protocol required all countries to stabilize the emissions of nitrogen oxide, and some countries decided to reduce the emissions up to 30%. In 1988 all European Community countries were required to reduce sulfur dioxide and nitrogen oxide emissions from power plants. In the United States the first project to reduce emissions released from power plants was the Clean Air Act in the early 1990 s. This act limited sulfur dioxide emissions from 110 of the largest power plants to a combined total of 8.7 million tons of sulfur dioxide: about 10 million tons less than those plants had emitted annually during ( IN 1999 the NOx budget program limited nitrogen oxide emissions from power plants and other sources.

5 Just recently in 2002 the Clear Skies programs took effect. This program wants to cut sulfur dioxide by 73% and nitrogen oxides by 67% by 2018 ( Many alternative energy sources are being investigated and placed into use in order to cut down on emissions. Some of the alternative energy sources are nuclear power, hydropower, wind energy, geothermal energy, and solar energy. Locally there are many things an individual can do to cut back on emissions that contribute to acid rain. The following list is a number of things people can do in their everyday lives to help cut down on acid rain. - Turn off lights, computers, and other appliances when you're not using Them. - Use energy efficient appliances: lighting, air conditioners, heaters, refrigerators, washing machines, etc. - Only use electric appliances when you need them. - Keep your thermostat at 68 F in the winter and 72 F in the summer. You can turn it even lower in the winter and higher in the summer when you are away from home. - Insulate your home as best you can. - Carpool, use public transportation, or better yet, walk or bicycle whenever possible - Buy vehicles with low NOx emissions, and maintain all vehicles well. Acid rain is a relatively new hazard to the environment and humans. Unfortunately humans are the one that brought about this hazard due to the advances in technology. Power plants and cars are the major contributors to the emissions of sulfur dioxide and nitrogen oxide, which cause acid rain. Many natural elements and man-made structures are being affected negatively by acid rain, along with human s health. Ever since acid rain was acknowledge as a problem many solution have been adopted by countries to cut back on

6 emissions. Hopefully one day countries will only be using alternative energy sources which would cut back dramatically on emissions released into the atmosphere. Maybe one day acid rain will only occur natural in the world.

7 Bibliography September 25, September 25, September 25, 2003