Saturday, November 5, 2011


All hell was let loose with the recent news that there is an expected shower of acid rain across the geographical region of Nigeria. The mass media, both electronic and print, the internet, as well as mouth to mouth information have all been awash by stories of a looming bout of acid rain.

In the wake of an SMS which was sent out to a large number of people, informing them of an oncoming acid rain which was misconstrued to cause cancer and death. The full text of the message reads thus:

Be careful from the 20th to 28th of this month, there is possibility of an ACID RAIN. The dark circle appeared around the moon on 17th of last month & this is an indication of Acid Rain. Apparently this happens once in 750yrs. It rains normally but It may cause skin cancer if you expose yourself to it. So ALERT your dear ones. This information is from NASA in the USA. DO NOT neglect. Please forward this to your friends. Better to be cautious than sorry.

Granted, bad news is expected to spread with more voracity and intensity, this explains how and why the current wave of stories about the acid rain has circulated across Nigeria. But some reasonable questions to be asked are: what is an acid rain, and is it a new occurrence? What are the effects of acid rain? How come it is just beginning to take preeminence in the minds of people?

First, let us understand the phenomenon described as acid rain and shed more light on the principles that govern its formation, activation and eventual release.

What is an acid rain?
Acid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rain is caused by emissions of compounds of ammonium, carbon, nitrogen, and sulfur which react with the water molecules in the atmosphere to produce acids.

What is the history of acid rain?
Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides to the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England. Though acidic rain was discovered in 1852, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. The term "acid rain" was generated in 1972. Canadian Harold Harvey was among the first to research a "dead" lake. Public awareness of acid rain in the U.S increased in the 1970s after the New York Times promulgated reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects demonstrated to result from it.

What are the effects of acid rain?
Surface waters and aquaticv animals
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 pHs lower than 5 most fish eggs will not hatch and lower pHs 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 pHs and are killed. The enzymes of these microbes are denatured (changed in shape so they no longer function) by the acid. The hydronium ions of acid rain also mobilize toxins such as aluminium, and leach away essential nutrients and minerals such as magnesium.

Forests and other vegetation
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.

Human health
Scientists have suggested direct links to human health. Fine particles, a large fraction of which are formed from the same gases as acid rain (sulfur dioxide and nitrogen dioxide), have been shown to cause illness and preature deaths such as cancer and other diseases.

Other adverse effects
Acid rain can also damage buildings and historic monuments, especially those made of rocks such as limestone and marble containing large amounts of calcium carbonate. Acids in the rain react with the calcium compounds in the stones to create gypsum, which then flakes off.

Clearly, it is obvious that the case of the recent alarm oozes out of the thoughts of some mischievous individuals or groups who decided to cash in on the wide gap of illiteracy in the country. Contrary to the contents of the SMS's that have been sent out, “Scientists have suggested direct links to human health.” and cancer have not been directly linked to acid rain.

The simple truth is that as long as we (humans) continue to embarrass mother nature and pollute her with our knack for comfort, we would in turn, be embarrassed by mother nature. Acid rain has been around for a very long time, it is as old as the very first time that we have released ammonium, carbon, nitrogen, and sulfur into the atmosphere.

Acid Rain – Control If Before It Ruins New Parts Of The Earth

Acid rain was a very common phenomenon before many governments stepped in to put an end to it. It is a term given to precipitation which contains various acids, but mostly sulfuric acid, which get formed when gases emitted by industry and vehicles combine with water droplets in the air. Acid rain is the most common term for this precipitation although it can also take the form of snow or fog depending on the climactic conditions of the place where it occurs. Acid rain or snow has a devastating effect on the land where it falls. It can destroy vegetation as well as animal life. Trees are stripped bare of their leaves when this rain falls on them. It can also damage the soil for good, making it unfit for cultivation. The negative results of acid rain do not stop at this. The acids wash into rivers and lakes where they kill fish and other marine life mercilessly. Certain places at high altitudes have suffered greatly as a result of these acids especially when trees in these places are surrounded by acid fog for extended periods of time. Acid rain is mostly caused due to the presence of sulfur dioxide in industrial emissions that combine with water particles to form sulfuric acid. Nitrogen dioxide in emissions causes nitric acid to be formed in the same way. Governments have stepped in to regulate emissions from various factories. They have to make certain modifications to their chimneys whereby these gases are not allowed to escape into the atmosphere. This involves the use of new technology, especially in the form of a wet scrubber that converts these gases into other products. A lot of nitrogen oxide also escapes in the form of automobile emissions. Steps are being taken to control these emissions in order to reduce the pollution of the environment. While many developed nations have already put many environmental measures and laws in place, the spotlight has now shifted to developing nations. Pollution is on the increase in these countries and they do not all have access to technology or money to control emissions. Besides, these countries resent the attempts by developed nations to curtail their industrial growth after the developed nations have already created substantial wealth after destroying the environment. It is now up to each individual to do something to help save the planet from acid rain. The choices we make in terms of the products we use have a direct bearing on the health of our planet and out future on it. International treaties and discussions are in place to put an end to acid rain. It will require the cooperation of all countries in order to make this venture a success. After all, rain clouds know no boundaries and pollution in one country can lead to acid rain in another country. The problem of industrial pollution and acid rain has to be tackled on a war footing because if it allowed to continue the results could be devastating for the earth.

What Is Acid Precipitation?

Acid precipitation is more commonly referred to as acid rain, but can also mean sleet, snow, fog, or mist with an unusually high acid component. Precipitation is generally considered to be acid if the pH is lower than 5.6, compared to pure distilled water, which has a pH of 7.0. Acid precipitation is considered by many experts to be a potentially environmentally devastating phenomena often associated with global warming and high greenhouse gas levels.

Certain chemical emissions, such as sulfur or nitrogen dioxide, are considered mainly responsible for increased levels of acidity in precipitation. When these chemicals are released into the air, they can mix with water-bearing chemicals and become part of the cloud makeup. When a cloud releases water in the form of rain, snow, or sleet, the absorbed chemicals increase the acidic content of the water, resulting in acid precipitation.

High levels of acid rain are linked to areas with heavy industrial usage and high vehicle density. The emissions from cars, buses, and industrial plants are all associated with high levels of acid in precipitation. In the United States, the Northeastern states typically show the highest level of acid precipitation, which most experts consider to be a direct result of the urban and industrial density throughout the region. According to some studies, average acidity levels for precipitation in the Northeastern states can be as low as 4.3 on the pH scale.

The damage caused by acid precipitation has long been studied but is only recently being given serious attention. Studies on acid rain have been conducted since at least the 19th century, when Scottish scientist Robert Angus Smith published a book on the effects of local industry pollution on air, land and local agriculture. Since Smith’s time, detailed scientific studies have suggested links between acid rain and severe ecological damage to water sources and soil as well as human and animal existence.

Acid precipitation can be devastating to both freshwater and marine ecosystems. In addition to raising the acid content of the water, high acid levels can also deteriorate bedrock systems, allowing hard metals stored in the rocks to seep into the water. Many experts attribute falling fish counts to a buildup of mercury in fish habitats, largely due bedrock excretions of the chemical.

High acidic content in rain and other forms of precipitation can also destroy the nutritional value of topsoil, starving crops of necessary nourishment. The alterations to soil makeup can prove deadly to certain plant species, such as maple trees, that are dependent on low acid soil in order to grow. Some studies suggest that the centuries-old market for maple sugar and syrup is greatly endangered thanks to loss of maple trees.

Even human invention risks damage from acid precipitation. In urban areas with high levels of acid rain, monuments, historical buildings, and artwork exposed to the elements are often endangered by acid rain. Traditional building materials such as marble and limestone include a calcium content that is easily damaged by high acidity, while metals like copper and bronze quickly oxidize in acidic conditions, leading to blemishes and discoloration. Famous buildings such as the Parthenon, the Lincoln Memorial, and the Taj Mahal are all under careful observation after showing signs of material erosion thanks to acid precipitation.

Harmful Consequences of Acid Rain

Pollution causes impurities to rain water and turning it to acidic substance. It is said that rain water contains many minerals and it is good for the skin and hair. However, due to the pollutants on it, it is not pure anymore. Acid rain can bring negative effects on plants, animals and even human beings. In this article, the causes of acid rain will be discussed as well as its effects on the life in the planet.

Pollutants and harmful gases such as carbon monoxide, nitrogen oxide and ammonium when mixed with rain water in the atmosphere, will turn the rain droplets acidic. High level of hydrogen ions in the rain water will result to the pH level of the water to drop below 7. Acid rain, if it will fall to the ground, will result to destruction of vegetation and other life forms.

Vegetation is one of the living things that can be affected by acid rainffected by acid rain. Acid rain causes damage to microorganisms in the soil that usually helps in biochemical processes. It also affects the pollination and reproduction of plants. Acid rain can remove the waxy coating of the plants, thus, making them prone to diseases.

Metals can be corroded by acid rain. Moreover, harmful metals such as aluminum and mercury can be leak into the soils and be washed to the bodies of water resulting to damage or even death of aquatic life. Not only will that fishes die, but greater amount of these harmful chemicals stocked in the body of fishes will cause harmful effects to humans.

Acid rain is also known to affect human beings. It can cause problems in the skin like burns and blisters. Too much acid in theuch acid in the rain can also lead to burning of the skin. Acid rain, according to doctors, can also cause skin cancer. Humans can have health problems due to acid rainue to acid rain by consuming plants and animals that contain harmful chemicals.

These are the facts about acid rain and how it can affect living things. May we perform our tasks as guardians of our mother nature.

Prevent Acid rain:

It's high times that we react, respond and do something to save our atmosphere from getting destroyed.Let's go by the saying that prevention is better than cure.I have mu own suggestions to say:

1)Make the less use of automobiles.Use cycles or non-polluted vehicles for nearby purposes keeping aside the matter of dignity and status.

2)Use electric cars which run on battery to prevent acid rain.Though electric cars are not a big hit try using them for minor uses and and new formula is to be invented for battery based vehicles.

3)Industries must reduce the sulfur content from the smoke they release. The smoke should be checked before they are released into the atmosphere.

4)Find new ways and methods to burn coal or else replace current and electricity for these means and get the maximum out of it.

5)Government should get into the picture, play an active role and check the pollution levels of factories, industries and automobiles and vehicles.

6)developing countries should learn from the developed countries and curb the destruction as drop and drop only make a big ocean.

If at least some the methods are implemented the effects of scid rain can be reduced in the coming future days.

How is Acid Rain Formed

What is acid rain?
Acid rain is classified as any form of precipitation (rain, snow, fog, hail) that has a pH of 4 or lower. It is primarily a result of air pollution. Particular gases released into the atmosphere react with the water particles in clouds and combine to make a very weak form of acid. Acid rain can have harmful effects on plant life, water supplies and aquatic life and some forms of infrastructure. Acid rain is not acidic enough to burn your skin upon contact. The acid that is formed in the atmosphere can also fall as acidic dust and pollute the soil many thousands of kilometers from the source of the pollution.

How is acid rain formed?
There are three main causes of acid rain, but both are due to the same gases being released into the atmosphere. Acid rain is caused by the two main air pollutants, sulfur dioxide and nitrogen oxide. When these gases come into contact with the hydrogen and oxygen molecules in water they combine to form a weak acid. The major cause of acid rain is air pollution by burning fossil fuels, smelting metals and motor vehicles. Acid rain can also be caused naturally by the eruption of a volcano. When a volcano erupts it produces a large amount of sulfur dioxide and it is not uncommon to have acid rain. Acid rain can also be caused by lightning strikes as these naturally produce nitrogen oxide.

How does acid rain effect the environment?
In the 1970’s the effects of acid rain were at their worst. Many forests the world over were dying and there were many cases where marine life in lakes and rivers died out or became mutated. Governments the world over worked to lower the amount of sulfur dioxide and nitrogen oxide that they were adding to the atmosphere. Acid rain is often felt in countries many thousands of kilometers from major air pollution. Mountainous regions are more likely to suffer from greater acid rain fall due to the higher rainfall received in these areas.

How to Avoid Acid Rain

Acid rain is a popular phrase used to describe rain, snow, fog, or other precipitation that is full of acids that collect in the atmosphere due to the burning of fuels such as coal, petroleum, and gasoline. Acid rain was first recognized in Europe in the late 1800s but did not come to widespread public attention until about 1970, when its harmful effects on the environment were publicized. Research has shown that in many parts of the world, lakes, streams, and soils have become increasingly acidic, prompting a corresponding decline in fish populations. Acid rain occurs when polluted gases become trapped in clouds that drift for hundreds, even thousands, of miles and are finally released as acidic precipitation. Trees, lakes, animals, and even buildings are vulnerable to the slow, corrosive effects of acid rain.

Acidification, the process of making acid, is not just caused by deposits of acidic rain but also by chemicals in snow and fog and by gases and particulates when precipitation is not occurring. The major human-made causes of acid deposition are (1) emissions of sulfur dioxide from power plants that burn coal and oil and (2) emissions of nitrogen oxides from automobiles. These emissions are transformed into sulfuric acid and nitric acid in the atmosphere, where they accumulate in cloud droplets and fall to Earth in rain and snow, wet deposition. Other sources of acid deposition are gases like sulfur dioxide and nitrogen oxides, as well as very small particulates. These gases and particulates are usually deposited when it is not raining or snowing which is called dry deposition.

While large areas of Europe and North America are exposed to acidifying depositions, only certain types of ecosystems are affected by these depositions. The most vulnerable ecosystems usually have a thin cover of soil, containing little calcium and sitting upon solid rock made up of hard minerals such as granite or quartz. Many freshwater lakes, streams, and rivers have become acidic, resulting in the decline or local destruction of some plant and animal populations. It is not yet certain that land-based ecosystems have been affected by acidic deposition. After acid rain was discovered in Europe, scientists began measuring the acidity of rain in North America. Initially, they found that the problem was concentrated in the northeastern states of New York and Pennsylvania because the type of coal burned there was more sulfur containing.

Acid rain is measured through pH tests that determine the concentration of hydrogen ions in a liter of fluid. The pH scale is used to measure acidity or alkalinity. It runs from 0 to 14. Water has a neutral pH of 7. The greater the concentration of hydrogen ions and the lower the pH number, the more acidic a substance is and the lower the concentration of hydrogen ions and the higher the pH number, the more alkaline or basic a substance is. So a pH greater than 7 indicates an alkaline substance while a pH less than 7 indicates an acidic substance. It is important to note that a change of only one unit in pH equals a tenfold change in the concentration of hydrogen ions. For example, a solution of pH 3 is 10 times more acidic than a solution of pH 4. Normal rain and snow measure about pH 5.60. In environmental science, the definition of acid precipitation refers to a pH less than 5.65.

Measured values of acid rain vary according to geographical area. When pH levels are drastically upset in soil and water, entire lakes and forests are endangered. Evergreen trees in high elevations are especially vulnerable. Although the acid rain itself does not kill the trees, it makes them more susceptible to disease. Also, high acid levels in soil cause leaching of other valuable minerals such as calcium, magnesium, and potassium. Small marine organisms cannot survive in acidic lakes and rivers, and their depletion affects the larger fish who usually feed on them, and, ultimately, the entire marine-life food chain. Snow from acid rain is also damaging; snowmelt has been known to cause massive, instant death for many kinds of fish. Some lakes in Scandinavia and New York's Adirondack Mountains are completely devoid of fish life. Acid rain also eats away at buildings and metal structures. From the Acropolis in Greece to Renaissance buildings in Italy, ancient structures are showing signs of corrosion from acid rain. In some industrialized parts of Poland, trains cannot exceed 40 miles (65 kilometers) per hour because the iron railway tracks have been weakened from acidic air pollution. Usually, waters affected by acid rain are treated by adding limestone or lime, an alkaline substance (base) that reduces acidity. Fishery biologists especially are interested in liming acidic lakes to make them more habitable for sport fish. In some parts of Scandinavia, for instance, liming is used extensively to make the biological damage of acidification less severe.

While neutralizing ecosystems that have become acidic, treats the symptoms but not the sources of acidification. Although exact sources of acid rain are difficult to pinpoint and the actual amount of damage caused by acid deposition is uncertain, it is agreed that acid rain levels need to be reduced. Scientific evidence supports the notion that what goes up must come down, and because of public awareness and concerns about acid rain in many countries, politicians have begun to act decisively in controlling or eliminating human causes of such pollution. Emissions of sulfur dioxide and nitrogen oxides are being reduced, especially in Western Europe and North America. For example, in 1992 the governments of the United States and Canada signed an air-quality agreement aimed at reducing acidifying depositions in both countries. While countries in Western Europe and North American have actively carried out actions to reduce emissions of gases leading to acid deposition for a number of years, countries in other parts of the world have only recently addressed the issue. In Eastern Europe, Russia, China, India, Southeast Asia, Mexico, and various developing nations, acid rain and other pollution problems are finally gaining notice. For example, in 1999, scientists identified a haze of air pollution that hovers over the Indian Ocean near Asia during the winter. The 3.8 million-square-mile haze (about the size of the combined area of all fifty American states) is made up of small by-products from the burning of fossil fuels. Such a cloud has the potential to cool Earth, harming both marine and terrestrial life.

Effects of acid rain on automotive coatings

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 seriously reduce the value to society of buildings, bridges, cultural objects (such as statues, monuments, and tombstones), and cars.

Over the past two decades, there have been numerous reports of damage to automotive paints and other coatings. The reported damage typically occurs on horizontal surfaces and appears as irregularly shaped, permanently etched areas. The damage can best be detected under fluorescent lamps, can be most easily observed on dark colored vehicles, and appears to occur after evaporation of a moisture droplet. In addition, some evidence suggests damage occurs most frequently on freshly painted vehicles. Usually the damage is permanent; once it has occurred, the only solution is to repaint.

The general consensus within the auto industry is that the damage is caused by some form of environmental fallout. "Environmental fallout," a term widely used in the auto and coatings industries, refers to damage caused by air pollution (e.g., acid rain), decaying insects, bird droppings, pollen, and tree sap. The results of laboratory experiments and at least one field study have demonstrated that acid rain can scar automotive coatings. Furthermore, chemical analyses of the damaged areas of some exposed test panels showed elevated levels of sulfate, implicating acid rain.

The popular term "acid rain" refers to both wet and dry deposition of acidic pollutants that may damage material surfaces, including auto finishes. These pollutants, which are released when coal and other fossil fuels are burned, react with water vapor and oxidants in the atmosphere and are chemically transformed into sulfuric and nitric acids. The acidic compounds then may fall to earth as rain, snow, fog, or may join dry particles and fall as dry deposition. Automotive coatings may be damaged by all forms of acid rain, including dry deposition, especially when dry acidic deposition is mixed with dew or rain. However, it has been difficult to quantify the specific contribution of acid rain to paint finish damage relative to damage caused by other forms of environmental fallout, by the improper application of paint or by deficient paint formulations. According to coating experts, trained specialists can differentiate between the various forms of damage, but the best way of determining the cause of chemically induced damage is to conduct a detailed, chemical analysis of the damaged area.

Because evaporation of acidic moisture appears to be a key element in the damage, any steps taken to eliminate its occurrence on freshly painted vehicles may alleviate the problem. The steps include frequent washing followed by hand drying, covering the vehicle during precipitation events, and use of one of the protective coatings currently on the market that claim to protect the original finish.

The auto and coatings industries are fully aware of the potential damage and are actively pursuing the development of coatings that are more resistant to environmental fallout, including acid rain. The problem is not a universal one-- it does not affect all coatings or all vehicles even in geographic areas known to be subject to acid rain-- which suggests that technology exists to protect against this damage. Until that technology is implemented to protect all vehicles or until acid deposition is adequately reduced, frequent washing and drying and covering the vehicle appear to be the best methods for consumers who wish to minimize acid rain damage. (EPA)

What Are the Different Types of Acid Rain Damage?

Acid rain is precipitation contaminated with highly acidic particles. It occurs both as a result of natural activity, such as volcanic eruptions, and the collection of man-made particulate matter and emissions in the atmosphere. According to many environmental experts and scientists, severe environmental and even structural damage can be caused by acid rain, leading many to call for updated emission standards that would reduce man-made acid precipitation.

When certain chemical gases such as sulfur dioxide, ammonium, or nitrogen are expelled into the atmosphere, they can combine with water molecules to create acid-heavy clouds. These clouds may be propelled by the wind and atmospheric changes, eventually releasing precipitation in the form of acid rain, snow, sleet, fog, or other types of precipitation. Damage is caused when the acidic nature of this precipitation mixes with whatever it hits, including soil, stone, plants, or water.

Acid rain damage takes many forms and can have many outcomes. Generally, the precipitation causes alteration to the pH balance of whatever it touches, resulting in changes to the chemical makeup. According to studies, these chemical alterations can have devastating effects on all types of ecosystems and may even pose danger to human health and civilization.

Nutrient depletion in soil is one common type of acid rain damage. As the acidic water compounds hit the soil, they can leach out vital nutrients that make soil fertile. Enough contamination can lead to patches of soil becoming unable to support life, cutting off the nutritional feed line to any plants in the affected area. The chemical compounds in the rain disperse in the soil, allowing the accumulation of harmful chemicals, such as aluminum, that can kill plants. From this point on, the destruction accumulates, as the resulting die-off of plants leads to diminished habitat and food sources for resident animal, bird, and insect populations.

Acid rain damage can also be extremely dangerous to water-based ecosystems. As the acidic water falls into a lake or stream, the pH balance drops and harmful chemicals, like aluminum and mercury, are released into the body of water. Many aquatic species are extremely sensitive to acid and cannot hatch eggs or survive in contaminated waters; additionally, increased acid levels may kill aquatic plants and micro-organisms, destroying the main food sources of many aquatic creatures.

In human society, some studies have linked high acid rain damage to cancers and other illnesses. This dangerous precipitation also can be extremely destructive to certain types of stone, such as limestone and marble, and has caused severe damage to many ancient buildings, bridges, monuments, and works of art. Acid rain damage has caused many governments to enact protective and restoration efforts to preserve national monuments, including the Statue of Liberty in New York, and the Parthenon in Athens.

Acid rain- its effects and control measures

When fossil fuels such as coal, oil and natural gas are burned, chemicals like sulfur dioxide and nitrogen oxides are produced. These chemicals react with water and other chemicals in the air to form sulfuric acid, nitric acid and other harmful pollutants like sulfates and nitrates. These acid pollutants spread upwards into the atmosphere, and are carried by air currents, to finally return to the ground in the form of acid rain, fog or snow. The corrosive nature of acid rain causes many forms of environmental damage. Acid pollutants also occur as dry particles and gases, which when washed from the ground by rain, add to the acids in the rain to form an even more corrosive solution. This is called acid deposition.

Damage from acid rain is widespread in North America, Europe, Japan, China and South-east Asia. In the US, coal-burning power plants contribute to about 70% of sulfur dioxide. In Canada, oil refining, metal smelting and other industrial activities account for 61% of the sulfur dioxide pollution. Motor vehicle exhaust fumes are the main source of nitrogen oxides. The acids in acid rain chemically react with any object they come into contact with.

Effects of Acid Rain

1)Acid rain dissolves and washes away nutrients in the soil, which are needed by plants. It can also dissolve naturally occurring toxic substances like aluminum and mercury, freeing them to pollute water or poison plants.
2)Acid rain indirectly affects plants by removing nutrients from the soil in which they grow. It affects trees more directly by creating holes in the waxy coating of leaves, causing brown dead spots which affect the plant's photosynthesis. Such trees are also more vulnerable to insect infestations, drought and cold. Spruce and fir forests at higher elevations seem to be most at risk. Farm crops are less affected by acid rain than forest.
3)Acid rain that falls or flows as ground water to reach rivers, lakes arid wetlands, causes the water in them to become acidic. This affects plant and animal life in aquatic ecosystems.
4)Acid rain also has far reaching effects on wildlife. By adversely affecting one species, the entire food chain is disrupted, ultimately endangering the entire ecosystem. Different aquatic species can tolerate different levels of acidity. For example, clams and mayflies have a high mortality when water has a pH of 6.0. Frogs can tolerate more acidic water, although with the decline in supply of mayflies, frog populations may also decline. Land animals that are dependent on aquatic organisms are also affected.
5)Acid rain and dry acid deposition damages buildings, automobiles, and other structures made of stone or metal. The acid corrodes the materials causing extensive damage and ruins historic buildings. For example, the Parthenon in Greece and the Taj Mahal in India have been affected by acid rain.
6)Although surface water polluted by acid rain does not directly harm people, the toxic substances leached from soil can pollute the water supply. Fish caught in these waters may be harmful for human consumption. Acid, along with other chemicals in the air, produces urban smog, which causes respiratory problems.

Control Measures for Acid Rain

Improvement in technologies and switching to clean combustion technologies are highly essential. Coal with lower sulphur content is desirable to use in thermal plants. Replacement of coal by natural gas would also reduce the problem substantially. Installing scrubbers to reduce smoke stack emissions, though expensive, would be economical compared to the losses due to damage done to lakes, forests, monuments, food production and so on. Billions of dollars are spent in repairing the damage to buildings in Europe annually.

Chemistry of Acid Rain

In its purest state, rain water is like distilled water. It does not have carbon dioxide dissolved in it. It is neutral, with a pH level of 7. pH is the concentration of hydrogen ions in an aqueous solution. If the pH level is above 7, it is said to be basic, and if it is below 7, it is said to be acidic in nature.

As rain water falls through the atmosphere, particles suspended in the air are dissolved in it. These substances are generally dust, pollen grains and carbon dioxide (CO2). Emissions of volcanoes and lightning tend to decrease the pH level of acid rain, making it even more acidic. CO2 combines with water to form carbonic acid (H2CO3).

H2O(l) + CO2(g) = H2CO3(aq)

Carbonic acid ionizes in water to form low concentrations of carbonate and hydronium ions.

2H2O(l) + H2CO3(aq) = CO32-(aq) + 2H30+(aq)

Carbonic acid is a weak acid. It brings down the pH of the rain water to 6.0-5.2. With pH levels ranging between 6.0-5.2, rain water is acidic, but still not dangerous. This is a reversible reaction.

The problem occurs when rain water combines with gaseous oxides of sulfur, nitrogen, and phosphoric and hydrochloric acid mists. The latter two and sulfur are released into the atmosphere from automobile exhausts, industries and electric power plants. Nitrogen forms a major part of atmospheric composition. These chemicals bring down the acid rain pH level to 5.6-3.5. Sometimes, the pH level can even become as low as 2. This phenomenon of acidic rain water precipitation, is called acid rain. Rain, snow, sleet, freezing rain, hail, fog and dew are other forms of precipitation.

Chemistry of Acid Rain
Sulfuric acid and nitric acid are the main acids present in acid rain. Sulfuric acid is formed as follows:
Sulfur released into the atmosphere combines with atmospheric oxygen to form sulfur dioxide (SO2)
Sulfur dioxide reacts with atmospheric water to form sulfurous acid - SO2(g) + H20(l) = H2SO3(aq)
Sulfurous acid is also present in acid rain.
Sulfur dioxide gradually oxidizes to form sulfur trioxide (SO3) - 2SO2(g) = O2(g) = 2SO3(g)
Sulfur trioxide reacts with water to form Sulfuric acid (H2SO4) - SO3(g) + H20(l) = H2SO4(aq)
Nitrogen dioxide(NO2) is formed as follows:
Nitrogen combines with atmospheric oxygen to form nitrogen dioxide (NO2). Nitrogen dioxide reacts with water to form nitrous acid (HNO2) and nitric acid (HNO3) - 2NO2(l) + H2O(l) = HNO2(aq) + HNO3(aq)
Acid rain is a mild combination of mainly sulfuric and nitric acid. Sulfurous acid and nitrous acid are less stable and are present only in very low amounts. Following are the various adverse effects of acid rain on living organisms and infrastructure.

Buildings and Monuments: Acid rain causes severe damage to buildings and marble statues. Acid rain reacts with the calcium carbonate (CaCo3) to form soluble calcium hydrogen carbonate or calcium bicarbonate, Ca(HCO3)2 - CaCO3 + Acid rain = Ca(HCO3)2(aq)
Calcium bicarbonate is a powdery substance, which is easily washed away with water or more specifically, rain water. This is the way acid rain has partly eroded many world-famous monuments and buildings like the Taj Mahal in India, St. Paul's Cathedral in London, and the Statue of Liberty in New York.

Acid rain can destroy stained glass windows in churches, bridges made of steel, and railway tracks. It corrodes metal, ruins the paint color, weakens leather and forms a crust on glass surfaces.

Trees and Plants: Acid rain washes away important minerals from leaves and soil. Acid rain also blocks the small pores on the leaves' surface, through which they take in carbon dioxide. With improper functioning of leaves, the growth of trees gets retarded. This results in a loss of leaves, stunted growth and damaged bark. Such trees are more prone to attacks by fungi and insects. This can even result in the death of trees.

Soil: Soil contains many harmful minerals such as mercury and aluminum. These elements can't be absorbed by plants and trees and are thus harmless. Upon contact with acid rain, these chemicals undergo chemical reactions with the acids. As a result, compounds of aluminum, lead and mercury are formed. Plants and trees can easily absorb these compounds. Such elements, which are extremely harmful to living forms, ultimately affect the entire food chain. These chemicals not only harm the flora, but also the animals that feed on them.

Water Bodies: Harmful substances like aluminum, lead and mercury, as discussed above, are washed away from the soil to neighboring water resources by the acid rain, thus resulting in water pollution. These chemicals and their acids do not allow the flora and fauna to grow and reproduce. This also results in depletion of oxygen levels in water, thereby making it difficult for fish to respire. They die due to suffocation and poisoning caused by the presence of these chemicals.

Birds that feed on fish that are affected by these harmful chemicals, accumulate these elements in their systems. These chemicals are then passed on to animals that feed on such birds. In this manner, chemicals get introduced to each trophic level of the food chain. In each trophic level, the concentration of chemicals gets multiplied. This phenomenon is known as biomagnification.

Human Health: Acid rain is harmful to human health. Drinking water contaminated by aluminium, mercury and lead is highly dangerous for human health.

Acids are very small and fine particles. They are normally in a liquid state. When they are present in the atmosphere, they easily enter the lungs while breathing. Research has proven that these particles can even lead to cancer.

Solutions to Acid Rain

Acid rain is potent enough to destroy life on Earth. It damages anything it comes in contact with. It ruins forests, water bodies, soil, infrastructure, and the health of living beings. It's high time we take all possible measures to control it. There is a solution to every problem, and acid rain is no exception. Take a look at the various measures we can take.Human beings should reduce the use of fossil fuels. This would lessen the emission of nitrogen and sulfur in the environment. Public transportation, car pools and walking can reduce nitrogen, sulfur and lead emissions into the atmosphere. Sulfur and nitrogen are mostly released into the atmosphere from the burning of fossil fuels (e.g. Coal). Switching over to alternative forms of energy such as geothermal, water, wind, and solar power would help to a great extent.