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Acid rain facts for kids

Kids Encyclopedia Facts
Acid rain woods1
Acid rain can make the leaves fall off trees
- Acid rain damaged gargoyle -
A gargoyle that has been damaged by acid rain

Acid rain is rain that is unusually acidic. The acids are made when certain gases are carried high into the sky and react with the water in the atmosphere.

Acid rains can be harmful to plants, animals, and humans.

Robert Angus Smith is credited with the term "acid rain." In 1852, he showed the relationship between acid rain and atmospheric pollution in Manchester.

Causes

Origins of acid rain
Origins of acid rain

Although some natural gases, such as carbon dioxide, and gases from volcanoes can cause acid rain, it is now believed that mankind causes most acid rain. When people began building and using factories and power stations, they burned coal or oil. These compounds have sulfur in them that releases into the air, mixes with other elements, and produces acid rain.

Since the 1970's, governments have tried to clean smoke from factories and power stations in order to keep too much sulfur from rising to the atmosphere. This has had good results, but it is expensive.

In 2001, Great Britain still produced about five million tonnes (metric tons) of these gases every year, while China produced 18 million tonnes. The United States produced more than 20 million tonnes, but in 2010 that number fell to 8.1 million.

Adverse effects

Effects on lake ecology

Cloud formation from refinery in Curacao
Acid clouds can grow on SO2 emissions from refineries, as seen here in Curaçao

The pH level in lakes needs to be correct for fish to be able to survive, and acid rain can affect a lake's pH level. If there is too much acid in the water several things can happen:

  • The enzymes that help fish larvae to hatch will not be produced.
  • Aluminum travels more easily through water, causing fish to make more mucus around their gills. This makes it harder for fish to breathe.
  • Phytoplankton will not grow well and the animals that feed on it would suffer.

Effects on soil biology

Weathered limestone (20125209969)
Chemical weathering occurs when rocks are broken down by a chemical change - Acid rain is also a contributor to chemical weathering

Acid rain can damage soil by killing microbes that are needed in the soil. The hydrogen ions of acid rain also allow toxins to move in the soil and take away nutrients that the soil needs. Forests usually are the home to fungi, but acid rain changes the soil, making it more filled with bacteria. Many trees in the forest depend on the fungi for water and minerals, while the fungi take carbohydrates from the trees. This symbiotic relationship can be destroyed by acids.

Other adverse effects

MountMitchell
Mount Mitchell - These spruce-fir forests in the Appalachian Mountains have been damaged by introduced pests and 'acid rain' precipitation

Acid rain affects both living and non-living things. The leaves and roots of trees are damaged, making them less able to make food (photosynthesis) and absorb nutrients. Toxic ions released due to acid rain are dangerous to humans. It is believed that copper (mobilized by acids) has caused outbreaks of diarrhea in young children. Statues and other ancient structures have also been harmed by acid rain.

Prevention methods

Children play in the yard of a Ruston, Wash., home, while a Tacoma smelter stack showers area with arsenic and lead residue in August 1972
Children play in the yard of a Ruston, Washington home, while a Tacoma smelter stack showers area with arsenic and lead residue

In the U.S., the method for keeping sulfur from escaping into the air from the smokestacks of factories is called Flue Gas Desulfurization (FGD). One popular example is a wet scrubber, which pulls the gases from the stack into a tower and cleans them using lime or limestone. This changes the form of the chemical into a calcium sulfate that can be taken out of the scrubber. Sometimes the sulfates are sold to chemical companies. Other times, they are put in a landfill.

WET SCRUBBERS (CENTER OF PHOTO) WERE INSTALLED IN A $42 MILLION ENVIRONMENT IMPROVEMENT PROJECT AT THE PHILLIPS POWER... - NARA - 557304
Phillips Power Station wet scrubber facility

Some people do not want power generation to be controlled because they feel that pollution is a natural consequence of factories and power stations. They believe that if the pollution is not handled properly, it could be dangerous. Others install pollution controls for the benefits that they will receive from them.

Quick facts about acid rain

  • Acid rain is a result of gases mixing with water high in the atmosphere.
  • Sulfur dioxide is released into the air by machines, houses, and vehicles and is the main chemical that creates acid rain.
  • Acid rain makes it more difficult for aquatic (animals that live in water) life to survive.
  • Acid rain can damage the soil and the plants that live in it.
  • There are ways to prevent so much sulfur dioxide from escaping into the air. Many companies install pollution-controlling machinery into their factories.

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