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The Causes and Effects of Acid Rain

Acid rain is an environmental problem that knows no boundaries. The atmospheric pollution that causes it is carried by the prevailing winds from major industrial areas to the mountains, lakes and forests that lie to the east. It is a highly dangerous precipitation that can have serious impacts on the world's ecosystem. This kind of chemical rain can also appear in the form of fog, snow or even dust that settles on the earth as harmful toxins.

Not even the Arctic region is free of the air pollution that causes acid rain. Where does the acid come from? There is now no doubt that most comes from human activities - from cars, homes, factories and power stations. There has always been some acid in rain, coming from volcanoes, swamps and plankton in the oceans, but scientists know that it has increased very sharply over the past 200 years. Ice formed before the Industrial Revolution and trapped in glaciers which has been measured, and found to be just mildly acid, consistent with natural sources.

Rain is made acid mainly by two elements, sulfur and nitrogen. Sulfur is found in coal and oil. When burned, it turns to sulfur dioxide, which mixes with the water droplets in clouds and is then converted into sulfuric acid. Nitrogen, from the air and also in the fuel itself, is turned into oxides of nitrogen by burning, and then reacts with water molecules to form nitric acid. Some of the sulfuric and nitric acid falls locally, while the rest can be carried thousands of miles.

Since the 1950s, chimneys 500ft (150m) high have been built to carry pollution away from the urban areas, but their effect has been to spread it more thinly and more widely. This, coupled with the big increase in the amount of pollution, especially from power stations in recent decades, has resulted in places like Scandinavia being affected by pollution from factories in countries thousands of miles away. Swedish scientists have estimated that 70 percent of the sulfur in the air over Sweden comes from fuel burning, and that most of it comes from outside Sweden, particularly from Eastern Europe.

To discover if any of the acid rain was coming from the north-west like the British Isles, samples of air were collected by aircraft and tested by British scientists. On one flight it was found that air reaching the west coast of Britain across the Atlantic on the prevailing wind contained less than half as much sulfur and a quarter as much nitrate as air along the east coast. As it blew across Britain it had picked up the pollutants that it then carried to Scandinavia.

It was even possible to trace the 'plumes' of pollution from a particular power station by releasing a fluoride type of chemical from its chimneys. Instruments on the aircraft could tell when it was flying through that particular plume, and take measurements.

Dead wood trees due to acid rain

Dead wood trees due to acid rain

Further facts worth learning on acid rain:

  • Acid rain does not have a foul smell or a bad taste, it's usually like normal rain so it's rather unnoticeable.
  • Acid rain is not dangerous to human skin or hair, it will not burn or rot, but it's best to have a shower if you're likely to believe it's been raining acid due to today's bad climate.
  • Acid rain can discolor or damage a vehicle's paint. It also damages buildings and even statues on public display or in the garden.
  • Acid rain is still damaging lakes and aquatic animals, especially in Canada and US. Wetlands and streams are being affected too.
  • Acid rain is widespread in Canada because of toxic emissions like nitrogen oxide is coming from the US.
  • Acid rain destroys forests because it decays the leaves on the trees and cuts off their supply on sunlight and other nutrients required for healthy growth. Trees will not grow due to damaged soil from acid rain.
  • Active volcanoes emit massive amounts of sulphur dioxide into the air and is also responsible for creating acid rain chemicals.
  • Acid rain can be neutralized in areas where there's lime.
  • Acid rain can cause asthma, heart disease and cancer due to nitrogen oxide and sulfur dioxide.
  • Acid rain can cause respiratory problems if it's in the form of fog.
  • Acid rain can be produced from rotted plants and burning coal.
  • Last point, acid rain will decrease if pollution is not caused by humans anymore, it may even end for good.
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Gargoyle damaged by acid rain

Gargoyle damaged by acid rain


Zia Uddin (author) from UK on January 01, 2019:

Thanks for the comment FlourishAnyway.

FlourishAnyway from USA on December 31, 2018:

We are all connected and one part of the world certainly affects another. Those photos speak volumes.

Peggy Woods from Houston, Texas on December 08, 2018:

It is not surprising that pollution from one part of the world can affect other places far from it. While some causes of acid rain are natural, man-made causes could and should be curtailed.

Kenna McHugh from Northern California on November 29, 2018:

Zia, Your article has so much information about acid rain. I am impressed. Lime is a good solution to counter the acid. I am sure in those areas where it is heavy with acid rain the source is caused by human error - pollution. Someone once explained the prevailing winds how they determine where pollution or even nuclear fallout goes. It was an eye-opener.

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