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ECO CLUB PROJECT. ACID RAIN AND ITS HAZARDS. Sanjana Vasudevan Vandana.L.Pandya Nidhi.P.Bafna Harith Shanma.A.S. Kavithambika.S. Divya Kannika Ruchika Ranka Swathi.S. Atulaa Krishnamurthy. OUR TEAM :. INTRODUCTION.
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ACID RAIN AND ITS HAZARDS
Sanjana Vasudevan Vandana.L.Pandya Nidhi.P.Bafna Harith Shanma.A.S. Kavithambika.S. Divya Kannika Ruchika Ranka Swathi.S. Atulaa Krishnamurthy OUR TEAM :
INTRODUCTION • Asia is currently the region most effected by acidification. Acid rain primarily results from the transformation of Sulphur dioxide ( SO2) and Nitrogen oxide in to Sulphuric acid(H2SO4), Ammonium nitrate (NH4NO3) and Nitric acid(HNO3). • The transformation of SO2 and NO2 to acidic particles and vapours occurs as these pollutants are transported in the atmosphere over distances of hundreds to thousands of kilometers .Wet deposition is acid rain, the process by which acids with a pH normally below 5.6 are removed from the atmosphere in rain ,snow, sleet or hail. The gases can then be converted into acids when they contact water. A pH scale is used to measure the amount of acid in liquid-like water. Because acids release hydrogen ions , the acid content of a solution is based on concentration of hudrogen ions and is expressed as “pH”. This scale is used to measure the acidity of rain samples. • The smaller the number on the pH scale , the more acidic the substance is. Rain measuring between 0 and 5 on the pH scale is acidic and therefore called “acid rain". Small number changes on the pH scale actually mean large changes in the acidity.
CAUSE OF ACID RAIN • Sulphur dioxide (SO2) is generally b by-product of industrial processes and burning of fossil fuels . Ore smelting , coal-fired power generators and natural gas processing are the main contributors. • The main source of NOx emissions is the combustion of fuels in motor vehicles , residential and commercial furnaces ,industrial and electical-utility boilers and engines, and other equipments. • Effect of acidic rain on aquatic ecosystem: • Acid rain is caused by chemical reaction of that begins when compounds like sulphur dioxide an nitrogen oxides are released in to air .These substances can rise vary high in to the atmosphere, where they mix and react with water, oxygen and other chemicals to form more acidic • Most biological life survives best within a narrow range of pH levels , near neutral or 7.0. • Aquatic vegetation and animal life vary in their susceptibility to changes in pH ;some species are more acid-tolerant than others. Species higher up the food chain that relies on these organisms for food will be effected. If the pH levels drop below 5.0 most fish species are effected.
Effect of acid rain on soils and plant growth: • Some plants are tolerant of acidic conditions, while others are not. Acidic soils may affect micro organisms in the soil, which play important roles in plant growth. Acidity affects the availability of nutrients that are essential for plant growth. Nitrogen is a nutrient and at certain levels, nitrogen deposition from air emissions has increased growth of vegetation; however, at higher levels, excess nutrients can reduce plant growth. Plant leaves get burnt and dry. • Effect of acid rain on buildingsand materials: • Acid rain is corrosive of metals and alkaline building materials such as marble and limestone. Urban areas subject to high levels of automobile exhaust and other sources of acid rain have experienced significant weathering of statues and building materials. The important example of this is TAJ MAHAL, which looks darkened or yellow due to acid rain caused by oil refinery near by. • Effect of acid rain on health: • Acidic rain does not affect human health directly; however, the particulate matter associated with acid rain has been shown to have adverse health effects, particularly among those who have respiratory disorders.
There is also some concern that acidic rain could contribute to leaching of • toxins such as mercury that could be carried by runoff into bodies of water, contributing environmental sources of this toxin. • Acid rain is caused by a chemical reaction that begins when compounds like Sulphur dioxide and Nitrogen oxides are released into the air. These substances can rise very high into the atmosphere, where they mix and react with water, oxygen and other chemicals to form more acidic pollutants, known as acid rain. Sulphur dioxide and nitrogen oxides dissolve very easily in water and can be carried very far by the wind. As a result, the two compounds can travel long distances where they become part of the rain, sleet, snow, and fog that we experience on certain days. • Human activities are the main cause of acid rain. Over the past few decades, humans have released so many different chemicals into the air that they have changed the mix of gases in the atmosphere. Power plants release the majority of sulphur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity. In addition, the exhaust from cars, trucks, and buses releases nitrogen oxides and Sulphur dioxide into the air. These pollutants cause acid rain. SOURCE OF ACID RAIN
Acid rain is caused by reactions in the environment: Nature depends on balance, and although some rain is naturally acidic, with a pH level of around 5.0, human activities have made it worse. Normal precipitation-such as rain, sleet, or snow-reacts with alkaline chemicals, or non-acidic materials, that can be found in air, soils, bedrock, lakes, and streams. These reactions usually neutralize natural acids. However, if precipitation becomes too acidic, these materials may not be able to neutralize all of the acids. Over time , these neutralizing materials can be washed away by acid rain. Damage to crops, trees, lakes, rivers, and animals can result. Acid rain causes acidification of lakes and streams and contributes to the damage of trees at high elevations (for example, red spruce trees above 2,000 feet) and many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures that are part of our nation’s cultural heritage. Prior to falling to the earth, sulphur dioxide(SO2 ) and nitrogen oxide (NOx) gases and their particulate matter derivatives- sulphates and nitrates- Effects of Acid Rain:
Contribute to visibility degradation and harm public health. Over the years, scientists, foresters, and others have noted a slowed growth of some forests. Leaves and needles turn brown and fall off when they should be green and healthy. In extreme cases, individual trees or entire areas of the forest simply die off without an obvious reason. After much analysis, researchers now know that acid rain causes slower growth, injury, or death of forests. Acid rain has been implicated in forest and soil degradation in many areas of the eastern U.S., particularly high elevation forests of the Appalachian Mountains from Maine to Georgia that include areas such as the Shenandoah and Great Smoky Mountain National Parks. Of course, acid rain is not the only cause of such conditions. Other factors contribute to the overall stress of these areas, including air pollutants, insects, disease, drought or very cold weather. In most cases, in fact, the impacts of acid rain on trees are due to the combined effects of acid rain and these other environmental stressors. After many years of collecting information on the chemistry and biology of forests, researchers are beginning to understand how acid rain works on the forest soil, trees, and other plants Effects of Acid Rain-Forests:
Acid rain on the Forest Floor • How Acid rain harms trees • How acid rain affects other plants • A spring shower in the forest washes leaves and fails through the trees to the forest floor below. Some trickles over the ground and runs into streams, rivers, or lakes, and some of the water soaks into the soil. That soil may neutralize some or all of the acidity of the acid rainwater. This ability is called buffering capacity, and without it , soils become more acidic. Differences in soil buffering capacity are an important reason why some areas that receive acid rain show a lot of damage, while other areas that receive about the same amount of acid rain do not appear to be harmed at all. The ability of forest soils to resist , or buffer, acidity depends on the thickness and composition of the soil, as well as the type of bedrock beneath the forest floor. Midwestern states like Nebraska and Indiana have soils that are well buffered. Places in the mountainous northeast, like New York’s Adirondack and Catskill Mountains, have thin soils with low buffering capacity. Acid Rain on the Forest Floor:
HOW ACID RAIN HARMS TREES: Acid rain does not usually kill trees directly. Instead, it is more likely to weaken trees by damaging their leaves, limiting the nutrients available to them, or exposing them to toxic substances slowly released from the soil. Quite often, injury or death of trees is a result of these effects of acid rain in combination with one or more additional threats. Scientists know that acidic water dissolves the nutrients and helpful minerals in the soil and then washes them away before trees and other plants can use them to grow. At the same time, acid rain causes the release of substances that are toxic to trees and plants, such as Aluminum, into the soil. Scientists believe that this combination of loss of soil nutrients and increase of toxic aluminum may be one way that acid rain harms trees. Such substances also wash away in the run off and are carried into streams, rivers, and lakes. More of these substances are released from the soil when the rainfall is more acidic. However, trees can be damaged by acid rain even if the soil is well buffered. Forest in high mountain regions often are exposed to greater amounts of acid than other forests because they tend to be surrounded by acidic clouds and fog that are more acidic than rainfall. Scientists believe that when leaves are frequently bathed in this acid fog, essential nutrients in their leaves and needles are stripped away. This loss of nutrients in their foliage makes trees more susceptible to damage by other environmental factors, particularly cold winter weather.
HOW ACID RAIN AFFECTS OTHER PLANTS: Acid rain can harm other plants in the same it harms trees. Although damaged by other air pollutants such as ground level ozone, food crops are not usually seriously affected because farmers frequently add fertilizers to the soil to replace nutrients that have washed away. They may also add crushed limestone to the soil. Limestone is an alkaline material and increases the ability of the soil to act as a buffer against acidity. Acid rain looks, feels, and tastes just like clean rain. The harm to people from acid rain is not direct. Walking in acid rain, or even swimming in an acid lake, is no more dangerous than walking or swimming in clean water. However, the pollutants that cause acid rain-sulphur dioxide (SO2) and nitrogen oxides (NOx)-do damage human health. These gases interact in the atmosphere to form fine sulphate and nitrate particles that can be transported long distances by winds and inhaled deep into people’s lungs. Fine particles can also penetrate indoors. Many scientific studies have identified a relationship between elevated levels of fine particles and increased illness and premature death from heart and lung disorders, such as asthma and bronchitis. Based on health concerns, SO2 and NOx have historically been EFFECT OF ACID RAIN: regulated under the Clean Air Act, including the Acid Rain Program. In the eastern
U.S., sulphate aerosols make about 25% of fine particles. By lowering SO2 and NOx emissions from power generation, the Acid Rain Program will reduce the levels of fine sulphate and nitrate particles and so reduce the incidence and the severity of these health problems. When fully implemented by the year 2010, the public health benefits of the Acid Rain Program are estimated to be valued at $50 billion annually, due to decreased mortality, hospital admissions, and emergency room visits. Decreases in NOx emissions are also expected to have a beneficial impact on human health by reducing the nitrogen oxides available to react with volatile organic compounds and form ozone. Ozone impacts on human health include a number of morbidity and mortality risks associated with lung inflammation, including asthma and emphysema. The acidification of surface waters causes little direct harm to people. It is safe to swim in even the most acidified lakes. However, toxic substances leached from soil can pollute local water supplies. In Sweden, as many as 10,000 lakes have been polluted by mercury released from soils damaged by acid rain, and residents have been warned to avoid eating fish caught in these lakes. In the air, acids join with other chemicals to produce urban smog, which can irritate the lungs and make breathing difficult, especially for people who already have asthma, bronchitis, or other respiratory diseases. Solid particles of sulphates, a class of minerals derived from sulphur dioxide, HUMAN HEALTH
are thought to be especially damaging to the lungs. Acid rain and the dry deposition of acidic particles contribute to the corrosion of metals (such as bronze) and the deterioration of paint and stone (such as marble and limestone) . These effects significantly reduce the societal value of buildings, bridges, cultural objects (such as statues, monuments, and tombstones), and cars. Dry deposition of acidic compounds can also dirty buildings and other structures , leading to increased maintenance costs. To reduce damage to automotive paint caused by acid rain and acidic dry deposition, some manufacturers use acid-resistant paints, at an average cost of $5 for each new vehicle (or a total of $61 million per year for all new cars and trucks sold in the U.S.).EPA’s Acid Rain Program will reduce damage to materials by limiting SO2 emissions. The benefits of EPA’s Acid Rain Program are measured, in part, by the costs now paid to repair or prevent damage-the costs of repairing buildings and bridges , using acid-resistant paints on new vehicles, plus the value that society places on the details of a statue lost forever to acid rain. EFFECT OF ACID RAIN-MATERIALS:
EFFORTS TO CONTROL ACID RAIN: • The following are some more specific suggestions on what you, as an individual, can do : • *In the home: • Run the washing machine with a full load. • Hang dry some or all of the laundry. • But energy-efficient appliances. • Avoid the use of air conditioners altogether. • Turn out the lights in empty rooms and when away from home. • Consider installing compact fluorescent bulbs instead of high-wattage incandescent bulbs. • If you have a forced-air furnace, change or clean its filters at least once a year. • Avoid burning trash or leaves.
While shopping: • Look for products bearing the EcoLogo. They minimize the use of environmentally hazardous substances and maximize energy efficiency and the use of recycled materials. • Buy locally produced or grown items from local stores and businesses. They don’t require the transportation energy of imported products. • Transportation. • Walk, ride your bike or take a bus to work. • Share a ride with a friend or co-worker. • Have your engine tuned at least once every six months. • Check your car tyre pressure regularly. • Use alternative fuels, such as ethanol, propane or natural gas. • Avoid unnecessary idling. • Reduce the number of trips you make in your car. • Drive at moderate speeds. • Take the train or bus on long trips. • Go CFC-Free. Control emission from vehicle. Check it regularly.Conserve energy.
Reduction in demand for oil and coal reduces the amount of acid rain. Acid Rain can best be curtailed by reducing the amount of sulfur dioxide and nitrogen oxides released by power plants, motorized vehicles, and factories. The simplest way to cut these emissions is to use less energy from fossil fuels. Individuals can help. Every time a consumer buys an energy-efficient appliance, adds insulation to a house, or takes a bus to work, he or she conserves energy and, as a result, fights acid rain. Another way to cut emissions of sulfur dioxide and nitrogen oxides is by switching to cleaner-burning fuels. For instance, coal can be high or low in sulfur , and some coal contains sulfur in a form that can be washed out easily before burning. By using more of the low-sulfur or cleanable types of coal, electrical utility companies and other industries can pollute less. The gasoline and diesel oil that run motor vehicles can also be formulated to burn more cleanly, producing less nitrogen oxide pollution. Clean-burning fuels such as natural gas are being used increasingly in vehicles. Natural gas contains almost no sulfur and produces very low nitrogen oxides. Unfortunately, natural gas and the less-polluting coals tend to be more expensive, placing them out of the reach of nations that are struggling economically. As far as possible let us try to adopt these control measures and reduce Acid Rain.
