Acid precipitation, more commonly known as acid rain, is rain that has been contaminated by air pollution. It is, therefore, more acidic than normal rain, that is rainwater with a pH value less than 5.0. Acid rain is generally formed when sulphur dioxide and nitrogen oxides, which are expelled into the atmosphere, undergo chemical change and are then absorbed by rain clouds. The acidic components are then disposed off with rain, snow or dew. This form of deposition increases soil acidity and causes a chemical imbalance in water sources. Acid rain kills frogs, fish and many kinds of plants. Numerous countries all over Europe are plagued by acid rain. Numerous lakes in Canada and Sweden have no fish due to acid rain. Countries in Europe and North America are the most active about tackling acid rain through measures to reduce pollution, especially sulphur dioxide emissions. Asia has emerged as the region most affected by acid rain – the use of high-sulphur coal is a major contributing factor. Acid rain also destroys and causes harm to man-made structures by causing corrosion in buildings.
Emissions that Lead to Acid Rain
Man-made: The biggest cause of acid rain is sulphur dioxide, most of which is emitted due to combustion of fossil fuels and during industrial processes. Also, nitrogen oxides, which go on to form nitric acid, are another major cause of acid rain. These sulphuric and nitrogen compounds are largely emitted by power plants, industrial units and cars. A major problem with industrial emissions is that they are easily carried over large distances through the atmosphere, thereby causing environmental problems over larger areas.
Natural phenomena: Emissions from volcanoes as well as other geological processes that occur on land, wetlands and oceans can contribute to the formation of acid-producing gases, with sulphur being the most common source. These natural emissions have been recorded in several glaciers across the world.
Types of Acid Rain or Deposition
Wet deposition: Acid rain in any form of precipitation—such as rain, snow or dew—that extract chemicals of acidic content from the earth's atmosphere come under the purview of wet deposition.
Dry deposition: Acid deposition can also occur without actual precipitation and is a common cause of acid rain in many areas. This form of deposition takes place when acidic particle remain on the ground or other objects close to the earth’s surface.
The impact of acid rain
Acid rain adversely impacts the ecosystem. While the impact on jungles, water sources, soil and several life forms is direct, the impact on other life forms is indirect. It is however, as devastating as acid rain finds its way into the food chain.
Acid rain has a very adverse impact on the soil. Numerous microbes within the soil are unable to cope with the high acidic content. Acid rain also causes the release of numerous toxins within the soil, destroying essential nutrients and minerals. Also, the damage to the soil affects the tree’s nutrient intake. Adverse effects on human health have only been suggested but none have been confirmed so far. Other effects include corrosion of buildings, especially those buildings which have calcium compounds in their stone.
Impact on water and acquatic species
Acid rain has a very damaging impact on lakes, streams, wetlands, and other aquatic environments. Acid rain makes waters acidic and causes them to absorb the aluminum that makes its way from soil into lakes and streams. This combination makes waters toxic to crayfish, clams, fish, and other aquatic animals.Fish are unable to spawn, and insect life dies out. In some cases, the damage has been so severe that several species have either joined the list of threatened, endangered or extinct species.
Some species can tolerate acidic waters better than others. However, in an interconnected ecosystem, what impacts some species eventually impacts many more throughout the food chain — including non-aquatic species such as birds.
Effect on plants
Acid rain also damages forests, especially those at higher elevations. It robs the soil of essential nutrients and releases aluminum in the soil, which makes it hard for trees to take up water. Trees' leaves and needles are also harmed by acids.
The effects of acid rain, combined with other environmental stressors, leave trees and plants less able to withstand cold temperatures, insects, and disease. The pollutants may also inhibit trees' ability to reproduce. Some soils are better able to neutralize acids than others. In areas where the soil's "buffering capacity" is low, the harmful effects of acid rain are much greater. Trees in forests get adversely affected by acid rain as their leaves and needles begin to wilt and fall off. effects of Acid Rain are such that, even if the plant survives the rainfall, it will most likely die soon after.
Effect on Animals
All ecosystems are highly interdependent. If for example a certain type of frog can survive high acidity level; the water beetles it preys on cannot, therby impacting the frog's food supply and indirectly the frog. The frog then dies out, and this process just continues up the food chain.
Effects on Humans
Humans are also impacted by the acid rain. Acid rain results in high mercury and aluminium content in the lakes and the in the fish that live in the lake. Mercury poisoning can make people sick and is pregnant women and smal children are asked to limit their fish intake for this reason. Aluminum can cause alzheimer’s disease. Acid Rain gets into the water, the soil and even the air. The latter is bad for asthma patients.
Possible solutions to acid rain
There are several ways acid rain and its impact can be managed. Lakes that have become acidic due to this can be treated with an alkaline substance called quicklime. This however, does not work on the bigger lakes as the flushing rates are too high and it just becomes acidic again.
To prevent Acid Rain, emission and pollution control laws ahave been introduced in many countries and across gegraphies. Factories are using scrubbers on there smoke stacks and are burning washed coal and coal with low sulfur content, all this reduces the gasses released.
There are also things that can be done at an individual level. People cna reduce their carbon footprint and food miles and practice energy conservation at their homes and workplaces. can do. Try to walk or ride your back short distances, this is good for your health and the environment. They can go for green buildings and reduce their carbon commute.
Did You Know?
- Acid rain is has been identified as one of the factors that have led to a 60 percent decline in the black duck population since 1955.
- Experts say that the ancient Mexican carvings at the pre-Aztec city of El Tajin are being erased by acid rain. 
- The Chinese government has calculated that acid rain, which has been growing at an alarming rate in the country thanks to the massive-scale coal burning, has resulted in economic losses worth $60 billion.
- Ten percent of all sulfur dioxide emission comes from volcanoes, sea spray, plankton, and rotting vegetation. Overall, 69.4 percent of sulfur dioxide is produced by industrial combustion. Only 3.7 percent is caused by transportation.
- Natural processes such as bacterial action in soil, forest fires, volcanic action, and lightning make up five percent of nitrogen oxide emission. Transportation makes up 43 percent, and 32 percent belongs to industrial combustion.
- Acid Rain
- Acid Rain and...
- Acid Rain--A Contemporary World Problem
- Environment Words—A Dictionary in Plain English, published By Images Asia
- Acid Rain