Acid rain may seem like a phenomenon of the past, but it is still a problem in many parts of the world, destroying entire ecosystems and damaging buildings and other structures. But what causes acid rain to begin with?
Acid Rain, as the name suggests, can be said as the precipitation of acid in the form of rain in the simplest manner. When atmospheric pollutants like oxides of nitrogen and sulphur react with rainwater and come down with the rain, then this result in Acid Rain. Acid rain is made up of highly acidic water droplets due to air emissions, most specifically the disproportionate levels of sulphur and nitrogen emitted by vehicles and manufacturing processes. It is often called acid rain as this concept contains many types of acidic precipitation. The acidic deposition takes place in two ways: wet and dry. Wet deposition is any form of precipitation which removes acids from the atmosphere and places them on the surface of the earth. In the absence of precipitation, dry deposition of polluting particles and gases sticks to the ground through dust and smoke.
The causes of acid rain are Sulphur and Nitrogen particles which get mixed with the wet components of rain. Sulphur and Nitrogen particles which get mixed with water are found in two ways either man-made i.e. as the emissions that are given out from industries or by natural causes like lightning strike in the atmosphere releasing nitrogen oxides and volcanic eruptions releasing sulphur oxide. According to the Royal Society of Chemistry, the word acid rain was invented in 1852 by Scottish chemist Robert Angus Smithwhich considers him the “father of acid rain. Smith decided on the word while studying rainwater chemistry near industrial towns in England and Scotland. The regular clean rain we experience, even though it is not clean i.e. water and carbon dioxide react together to form weak carbonicacid which essentially by itself is not extremely harmful.
The pH value of regular rainwater is around 5.7, giving it an acidic nature. The oxides of nitrogen and sulphur are blown away by the wind along with the dust particles. They settle on the earth’s surface after coming down in the form of precipitation. Acid rain is essentially a by-product of human activities which emit oxides of nitrogen and sulphur in the atmosphere. Example – the burning of fossil fuels, unethical waste emission disposal techniques.Sulphur dioxide and nitrogen dioxide undergo oxidation, and then they react with water resulting in the formation of sulphuric acid and nitric acid, respectively.
Acid rain is harmful to agriculture, plants, and animals. It washes away all nutrients which are required for the growth and survival of plants.The ecological consequences of acid rain are seen most strongly in marine habitats, such as streams, lakes and marshes where fish and other wildlife can be toxic. Acidic rainwater can leach aluminum from soil clay particles as it flows through the soil and then floods into streams and lakes. Acid rain affects agriculture by the way it alters the composition of the soil. It causes respiratory issues in animals and humans. When acid rain falls down and flows into the rivers and ponds it affects the aquatic ecosystem. It alters the chemical composition of the water, to a form which is actually harmful to the aquatic ecosystem to survive and causes water pollution. Acid rain also causes the corrosion of water pipes, which further results in leaching of heavy metals such as iron, lead and copper into drinking water
Acid rain damages the buildings and monuments made up of stones and metals, especially those constructed with limestone, react with the minerals and corrode them away. This leaves the buildings weak and susceptible to decay. Modern buildings, cars, airplanes, steel bridges and pipes are all affected by acid rain. Irreplaceable damage can be caused to the old heritage buildings. Acid rain leads to weathering of buildings, corrosion of metals and peeling of paints on surfaces. Building and structures made of marble and limestone are the ones especially damaged by acid rain due to the reactivity of acids in the rain and the calcium compounds in the structures. The live examples are, theTaj Mahal, one of the 7 wonders of the world, is largely affected by acid rain. The city of Agra has many industries which emit the oxides of sulphur and nitrogen in the atmosphere. People continue to use low-quality coal and firewood as a domestic fuel, adding to this problem. The formation of calcium sulphate results in the corrosion of this beautiful monument. Statue of Liberty which is made of copper has also been damaged by the cumulative action of acid rain and oxidation for over 30 years and is, therefore, becoming green.
The only precaution that we can take against acid rain is having a check at the emission of oxides of nitrogen and sulphur. Regulating the emissions coming from vehicles and buildings is an important step, according to the EPA. This can be done by restricting the use of fossil fuels and focusing on more renewable energy sources as well, such as nuclear power, hydropower, and geothermal energy, solar and wind power. Among these, the most extensive use is the nuclear and hydropower. Also, each person can do their part by reducing their vehicle use. Using public transportation, walking, riding a bike or carpooling is a good start, according to the EPA. People can also reduce their use of electricity, which is widely created with fossil fuels or switch to a solar plan. Renewable sources of energy are helping to reduce acid rain, as they produce much fewer emissions.
Acid rain is harmful to monuments. Sulphur dioxide and nitrogen oxide are the principal chemicals for acid rain. It can also influence humans since the acid goes into fruits, vegetables and animals. In other words, we can get really sick if acid rain doesn’t stop, and we eat those things. In general, acid rain affects men, but not directly.It is also possible to prevent acid rain forming, by adding lime deposits to major water sources. This method has been used to neutralize the pH levels in the water, which reduced the acidity, for thousands of years, the LA Times reported.
These so-called "liming" operations have also been used to restore wildlife. Being responsible citizens, one should be aware of the harmful effects they cause and of the industries which give out nitrogen and sulphur compound wastes unethically.
(The views expressed are personal)