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.