File Name: acid rain causes and effects .zip
Simply put, it means rain that is acidic in nature due to the presence of certain pollutants in the air due to cars and industrial processes. It is easily defined as rain, fog, sleet or snow that has been made acidic by pollutants in the air as a result of fossil fuel and industrial combustions that mostly emits Nitrogen Oxides NOx and Sulfur Dioxide SO2.
Acid rain is a rain or any other form of precipitation that is unusually acidic , meaning that it has elevated levels of hydrogen ions low pH. It can have harmful effects on plants, aquatic animals, and infrastructure. Acid rain is caused by emissions of sulphur dioxide and nitrogen oxide , which react with the water molecules in the atmosphere to produce acids.
Some governments have made efforts since the s  to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes, and sulphur dioxide is produced by volcanic eruptions. Distilled water , once carbon dioxide is removed, has a neutral pH of 7.
Liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are alkaline. Carbonic acid then can ionize in water forming low concentrations of carbonate and hydronium ions:. Unpolluted rain can also contain other chemicals which affect its pH acidity level.
A common example is nitric acid produced by electric discharge in the atmosphere such as lightning. The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn , who remarked upon the poor condition of the Arundel marbles.
In the late s, scientists began widely observing and studying the phenomenon. At first, the main focus in research lay on local effects of acid rain. Occasional pH readings in rain and fog water of well below 2. These areas all burn sulfur-containing coal to generate heat and electricity. The problem of acid rain has not only increased with population and industrial growth, but has become more widespread.
The use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation.
An example of this effect is the low pH of rain which falls in Scandinavia. The earliest report about acid rain in the United States was from the chemical evidence from Hubbard Brook Valley. In , a group of scientists including Gene Likens discovered the rain that was deposited at White Mountains of New Hampshire was acidic.
The pH of the sample was measured to be 4. Acid rain that mixed with stream water at Hubbard Brook was neutralized by the alumina from soils. Experimental research was done to examine the effects of increased acidity in stream on ecological species. In , a group of scientists modified the acidity of Norris Brook, New Hampshire, and observed the change in species' behaviors. There was a decrease in species diversity, an increase in community dominants, and a decrease in the food web complexity.
NAPAP looked at the entire problem from a scientific perspective. It enlarged a network of monitoring sites to determine how acidic the precipitation actually was, and to determine long-term trends, and established a network for dry deposition. Using a statistically based sampling design, NAPAP quantified the effects of acid rain on a regional basis by targeting research and surveys to identify and quantify the effects of acid precipitation on freshwater and terrestrial ecosystems.
NAPAP also assessed the effects of acid rain on historical buildings, monuments, and building materials. It also funded extensive studies on atmospheric processes and potential control programs. From the start, policy advocates from all sides attempted to influence NAPAP activities to support their particular policy advocacy efforts, or to disparage those of their opponents. In , the National Academy of Sciences was looking into research about the controversial issues regarding acid rain.
In , the panel of scientists came up with a draft report, which concluded that acid rain is a real problem and solutions should be sought.
In May , the House of Representatives voted against legislation that aimed to control sulfur emissions. There was a debate about whether Nierenberg delayed to release the report.
Nierenberg himself denied the saying about his suppression of the report and explained that the withheld of the report after the House's vote was due to the fact that the report was not ready to be published. Subsequent Reports to Congress have documented chemical changes in soil and freshwater ecosystems, nitrogen saturation, decreases in amounts of nutrients in soil, episodic acidification, regional haze, and damage to historical monuments.
Phase I began in , and limited sulfur dioxide emissions from of the largest power plants to a combined total of 8. Phase II began in , and affects most of the power plants in the country. During the s, research continued. This rule provides states with a solution to the problem of power plant pollution that drifts from one state to another. Overall, the program's cap and trade program has been successful in achieving its goals.
In , total SO 2 emissions were 8. The term citizen science can be traced back as far as January and a campaign by the Audubon Society to measure acid rain. The first recorded example of the use of the term is from , describing how volunteers across the US collected rain samples to assist the Audubon Society in an acid-rain awareness raising campaign.
The volunteers collected samples, checked for acidity, and reported back to the organization. The information was then used to demonstrate the full extent of the phenomenon. Because its remote conditions allowed for whole-ecosystem experiments, research at the ELA showed that the effect of acid rain on fish populations started at concentrations much lower than those observed in laboratory experiments.
The most important gas which leads to acidification is sulfur dioxide. Emissions of nitrogen oxides which are oxidized to form nitric acid are of increasing importance due to stricter controls on emissions of sulfur compounds. The principal natural phenomena that contribute acid-producing gases to the atmosphere are emissions from volcanoes. Acid-producing gasses are also created by biological processes that occur on the land, in wetlands , and in the oceans.
The major biological source of sulfur compounds is dimethyl sulfide. Nitric acid in rainwater is an important source of fixed nitrogen for plant life, and is also produced by electrical activity in the atmosphere such as lightning. Acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe. Soils of coniferous forests are naturally very acidic due to the shedding of needles, and the results of this phenomenon should not be confused with acid rain.
The principal cause of acid rain is sulfur and nitrogen compounds from human sources, such as electricity generation , animal agriculture , factories, and motor vehicles. Electrical power generation using coal is among the greatest contributors to gaseous pollution responsible for acidic rain. The gases can be carried hundreds of kilometers in the atmosphere before they are converted to acids and deposited. In the past, factories had short funnels to let out smoke, but this caused many problems locally; thus, factories now have taller smoke funnels.
However, dispersal from these taller stacks causes pollutants to be carried farther, causing widespread ecological damage. Combustion of fuels produces sulfur dioxide and nitric oxides. They are converted into sulfuric acid and nitric acid.
In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via an intermolecular reaction: . In the presence of water, sulfur trioxide SO 3 is converted rapidly to sulfuric acid :. Nitrogen dioxide reacts with OH to form nitric acid:. When clouds are present, the loss rate of SO 2 is faster than can be explained by gas phase chemistry alone.
This is due to reactions in the liquid water droplets. Sulfur dioxide dissolves in water and then, like carbon dioxide, hydrolyses in a series of equilibrium reactions:. There are a large number of aqueous reactions that oxidize sulfur from S IV to S VI , leading to the formation of sulfuric acid. The most important oxidation reactions are with ozone , hydrogen peroxide and oxygen reactions with oxygen are catalyzed by iron and manganese in the cloud droplets.
Wet deposition of acids occurs when any form of precipitation rain, snow, and so on removes acids from the atmosphere and delivers it to the Earth's surface. This can result from the deposition of acids produced in the raindrops see aqueous phase chemistry above or by the precipitation removing the acids either in clouds or below clouds. Wet removal of both gases and aerosols are both of importance for wet deposition.
Acid deposition also occurs via dry deposition in the absence of precipitation. Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms as well as causing damage to buildings and having impacts on human health.
Both the lower pH and higher aluminium concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pH lower than 5 most fish eggs will not hatch and lower pH can kill adult fish.
As lakes and rivers become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States.
Soil biology and chemistry can be seriously damaged by acid rain. Some microbes are unable to tolerate changes to low pH and are killed. The hydronium ions of acid rain also mobilize toxins , such as aluminium, and leach away essential nutrients and minerals such as magnesium. Soil chemistry can be dramatically changed when base cations, such as calcium and magnesium, are leached by acid rain, thereby affecting sensitive species, such as sugar maple Acer saccharum.
Impacts of acidic water and Soil acidification on plants could be minor or in most cases major. However, even in minor cases, the plant will eventually die due to the acidic water lowering the plant's natural pH. In major cases, which are more extreme, the same process of damage occurs as in minor cases, which is removal of essential minerals, but at a much quicker rate. If the leaves are green and look healthy, the soil pH is normal and acceptable for plant life.
But if the plant leaves have yellowing between the veins on their leaves, that means the plant is suffering from acidification and is unhealthy. Adverse effects may be indirectly related to acid rain, like the acid's effects on soil see above or high concentration of gaseous precursors to acid rain. High altitude forests are especially vulnerable as they are often surrounded by clouds and fog which are more acidic than rain. Other plants can also be damaged by acid rain, but the effect on food crops is minimized by the application of lime and fertilizers to replace lost nutrients.
In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands. When calcium is leached from the needles of red spruce, these trees become less cold tolerant and exhibit winter injury and even death. Acid rain has a much less harmful effect on oceans on a global scale, but it creates an amplified impact in the shallower waters of coastal waters.
These coastal species link together as part of the ocean's food chain, and without them being a source for other marine life to feed off of, more marine life will die. Acid rain does not directly affect human health. The acid in the rainwater is too dilute to have direct adverse effects. The particulates responsible for acid rain sulfur dioxide and nitrogen oxides do have an adverse effect.
Acid Rain: Causes, Effects and Solutions
Acid rain, or acid deposition, is a broad term that includes any form of precipitation that contains acidic components, such as sulfuric acid or nitric acid, according to the Environmental Protection Agency EPA. The precipitation is not necessarily wet or liquid; the definition includes dust, gasses, rain, snow, fog and hail. The type of acid rain that contains water is called wet deposition. Acid rain formed with dust or gasses is called dry deposition. The term acid rain was coined in by Scottish chemist Robert Angus Smith , according to the Royal Society of Chemistry, which calls him the "father of acid rain. In the s, scientists in the United States started studying the phenomenon, and in the s and early s, acid rain became recognized as a regional environmental issue that affected Western Europe and eastern North America.
The pH of precipitation undoubtedly is affected by a variety of natural sources of acidic and alkaline materials e. However, it has recently become apparent that rain and snow in certain regions of the earth are consistently more acidic than expected. Current data indicate that the mean annual pH in this region declined from 5. In eastern North America, precipitation is now more acidic than in Scandinavia. The median pH for ranged from 4.
Only a relatively small group of scientists seeking an explanation for the changes they observed in the environment were concerned with the problem. Today acid rain is recognized as an environmental problem of global proportions. Governments at all levels are moving to develop policies addressing the issue. As the topic has expanded from the scientific to the political arena, the public has become increasingly involved, and information sources have proliferated. Lovenburg, S. Report bugs here.
Bulger Jr. Acid deposition in any form is not harmful to humans, but the pollutants that cause acid.
Acid Rain and Water
Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature. Acid rain is mainly a mixture of sulphuric and nitric acids depending upon the relative quantities of oxides of sulphur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, protons are released causing increase in the soil acidity Lowering of soil pH mobilizes and leaches away nutrient cations and increases availability of toxic heavy metals.
A. Issue Definition
The solution to the problem of acid rain is perhaps one of the main environmental and political issues facing the peoples of the industrialized nations, and their neighbours today. There is no doubt about the damage which acid rain has caused, but what remains unclear are the precise causes of acid rain and the most efficacious means of reducing its environmental, economic and political impacts. We have presented a balanced look at the differing points of view on the current state of knowledge in acid rain research with respect to atmospheric processes, environmental effects, measurement procedures, and the legal and political issues surrounding acid rain. This review indicates that the atmospheric processes creating and transporting acid rain are not well enough understood to enable its reduction with any guarantee of success. This conclusion is based on the confusing or conflicting evidence presented by recent scientific studies.
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Acid rain is one of the consequences of air pollution. Gases produced from the burning of fuels react with the oxygen in the air and water vapour, transforming into acids that fall onto the earth's surface as rain. This acidification of the earth and surface water has devastating effects on ecosystems and poses a serious danger to living beings. The water and vapour emanating from Lake Kawah Ijen Indonesia , in the crater of the volcano of the same name, are lethal due to its high concentration of sulphuric acid. Volcanic eruptions, earthquakes, natural fires, lightning and some microbial processes release sulphur dioxide and nitrogen oxides into the atmosphere.
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