Causes of Acid Rain

Acid rain is a broad term used to describe several ways that acids fall out of the atmosphere.
A more precise term is acid deposition which has two parts wet and dry.
Some air pollution comes from natural sources, but most of them is man-made.
The burning of coal and oil (fossil fuels) by factories, homes and cars is the main source of chemicals that cause acid rain

Power stations and factories emit large amounts of sulfur dioxide and nitrogen oxide, whilst nitrous oxide from car exhausts adds to the problem.
Acid-polluted air can be blown by the wind over long distances.
The chemicals mix with rain and water vapor to produce weak solutions of sulfuric and nitric acids-acid rain-which eventually fall to earth.

The main cause of acid rain are gases called sulfur dioxide (SO₂) and nitrogen oxides (NOx).
These gases dissolve in the water in the atmosphere to make acids.
Bright sunlight speeds up the process, making the acid rain problem worse.
Although human activities cause most of acid rain, some acid rain occurs naturally.
Erupting volcanoes emit or give off smoke containing water vapor, carbon dioxide, sulfur dioxide and nitrogen compounds.
The sulfur dioxide and nitrogen causes small amounts of acid rain near the volcanoes.




Acid deposition has a variety of effects, including damage to forests and soils, fish and other living things, materials and human health.
Acid rain also reduces how far and how clearly we can see through the air an effect called visibility reduction.
Acid rain causes acidification of lakes and streams and contribute to damage of trees at high elevations and many sensitive fores 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 SO₂ and NO₂ gases and their particulate matter derivatives sulfates and nitrates contribute to visibility degradation and harm public health. The effects are listed below

1. Affect the human health
2. Affect the aquatic system
3. Visibility reduction
   
4. Effect on materials
   
5. Effect on Forests
6. Affect the ecosystem
7. Affect the lakes and streams

Acid rain is just one aspect of pollution but it is a very important one.
Like other forms of pollution it can be solved, but only if we are willing to spend time and money on cleaning up the processes that cause it. Industrialized processes that burn fossil fuels can be cleaned up by at three stages in the processes.

• Sulfur can be removed when the fuel is being burned. In this process coal is burned in a chamber containing limestone. As the coal burns, sulfur is absorbed by the limestone.
• After the fuel has been burned, the smoke and the gases given off by factories can be cleaned. A chemical in the factory chimney absorbs the sulfur in the gases.
• Natural gas can be used instead of coal or oil. It is less polluting than other fossil fuels.

Like many environmental problems, acid deposition is caused by the cumulative actions of millions of individual people.
Therefore, each individual can also reduce their contribution to the problem and become a part of the solution. Individuals can contribute directly by conserving energy, since energy production causes the largest portion of acid deposition problems.

The term "acid rain" was invented in 1872 by a British inspector appointed to prevent acids from soda factories in the United Kingdom from damaging nearby vegetation.
It was first thought that the solution to acid rain was to build higher smokestacks on furnaces, and to prevent polluting industries from becoming too concentrated geographically.
This remained the policy for more than a century; however it only served to disperse the problem.

• Fish began to disappear from European lakes in the 1930's
• By the late 1970's whole forests were beginning to die in eastern Europe. Canadian forests began to show the effects in 1982, followed by U.S and Japanese forests in 1984.
• Acid rain washes away the waxy protective coating of foliage, altering the chlorophyll used in photosynthesis.
• Poland the Czech Republic Slovakia and Hungary are among the most polluted countries in the world.
• The countries belonging to the organization for Economic cooperation and Development (OECD) generate approximately 41 million tons of nitrogen oxide every year.
• Acid rain is a rapidly growing threat in Mexico, China, Brazil and India.
• When Mount Saint Helens erupted in 1980, it emitted the same amount of sulfur dioxide in one day as a large coal fired power plant emits in one year.
• Acid rain and acid snow have even been found in remote polar regions, far from any polluting source.