Acidic gases like sulphur dioxide and nitrogen oxides are produced during the combustion of fossil fuels, like coal and oil in factories, thermal power plants, oil refineries, as well as gasoline and diesel in automobiles. These pollutants pollute the air.
Sulphur dioxide interacts with airborne water vapour to produce sulphuric acid, whereas nitrogen oxides interact with airborne water vapour to produce nitric acid. In general, clean water creates clouds of rain, but, when the gases in the atmosphere interact with the raindrops, there is the formation of acid rain.
Let's now talk about what acid rain actually is, how it forms, and how it affects the Taj Mahal.
What is acid rain?
Acid rain is made up of water droplets that are incredibly acidic. It forms as a result of air pollution, particularly the excessive amounts of sulphur and nitrogen emitted by vehicles and industrial processes.
Forms of acid rain
Wet and dry acidic depositions are the two different forms of acid rain.
Wet deposition:Any precipitation that removes acids from the atmosphere, and deposits them on the surface of the earth, is referred to as a wet deposition.
Dry deposition:In the absence of precipitation, detrimental dry deposition of particles and gases adheres to the ground, via dust and smoke. Consequently, it causes the creation of acid rain.
What causes acid rain? What is the cause of acid rain?
It is the end result of a number of human activities that cause sulphur and nitrogen oxides, to be released into the atmosphere. Burning fossil fuels that contain sulphur and nitrogenous substances is one example of this, such as coal and oil in furnaces and power stations, petrol and diesel in automobiles, etc.
Sulphuric acid and nitric acid are produced when sulphur dioxide and nitrogen dioxide are oxidized, followed by a reaction with water. As a result, sulphuric acid and nitric acid are the main producers of protons in rainwater, which ultimately causes acid rain.
When air is polluted, the aforementioned reaction happens more quickly. This is due to the fact that particulate matter in contaminated air, catalyses the reaction.
Normal rain formation
The typical rain we experience, despite the fact that it is not clean, is made up of mild carbonic acid, which is not particularly harmful on its own when water and carbon dioxide are combined. The following describes the reaction that is occurring:
CO2 (g) + H2O (l) = H2CO3 (aq.)
The pH of typical rainfall is around 5.7, which denotes that it is acidic. The wind carries the dust particles, nitrogen and sulphur oxides, and other pollutants away. They precipitate and then land on the earth's surface.
Process of acid rain formation
Sulphur and nitrogen particles react with the wet elements of rain to form acid rain.
There are two sources of sulphate and nitrate particles that combine with water: man-made (industrial emissions) and natural (a lightning strike in the atmosphere releases nitrogen ions, and volcanic eruptions releases sulphur).
Before reacting with water to form sulphuric acid and nitric acid, respectively, sulphur dioxide and nitrogen dioxide are oxidized.
The following reaction will shed light on the acid production reaction:
O2 (g) + 2SO2 (g) + 2H2O (l) = 2H2SO4 (aq)
O2 + 4NO2 + 2H2O. (aq) = 4HNO3
Effects of acid rain
1: Crops, plants, and animals all suffer significant losses as a result of acid rain. The nutrients required for plant growth and survival are destroyed. Because, acid rain alters the soil's chemical composition, it has an effect on agriculture.
2: It irritates both human and animal lungs.
3: When acid rain falls and flows into rivers and ponds, it affects the aquatic environment.
4:It causes water pollution and alters the chemical composition of the water, in a way that is damaging to the ability of aquatic ecosystems to thrive.
5: Acid rain causes water pipes to corrode. As a result, drinking water contains heavy metals like iron, lead, and copper.
6: It damages monuments and buildings made of stone and metal.
Causes of Acid Rain on Taj Mahal
The “Taj Mahal” is located in the city of “Agra”. Sulphur and nitrogen oxides are released in significant amounts by a number of nearby enterprises. Acidic gases like SO2, SO3, and NO2 react with atmospheric water vapour or rainwater, to produce sulphuric and nitric acids. The Taj Mahal's marble reacts with these acids to produce calcium sulphate and calcium nitrate.
What is the effect of acid rain on Taj Mahal?
The Taj Mahal in Agra is a magnificent historical building made entirely of white marble. Experts have warned that the Taj Mahal's white marble is gradually corroding and changing colour, due to air pollution in the area. This puts the Taj Mahal's beauty at peril!
The numerous businessesin Agra discharge gaseous pollutants into the atmosphere. These gases contribute to the acid rain. Thus, the Taj Mahal monument's marble (calcium carbonate) corrodes with time, as a result of acid rain's acids reacting with it.
Numerous factories in Agra emit nitrogen oxides and sulphur dioxide into the atmosphere. The problem is made worse by the continued use of poor-quality coal and firewood as domestic fuel. Marble (calcium carbonate) reacts with acid rain in the following ways:
CaSO4 + H2O + CO2 = H2SO4 + CaCO3
Acid rain-induced marble cancer is the progressive degradation (or eating away) of marble monuments. The pure white marble of the Taj Mahal turns yellow from the suspended particulate matter, such as soot particles, emitted in the smoke from different oil refineries.
Preventative measures to reduce the effects of acid rain on Taj Mahal
The only preventive action we can take to stop acid rain is to lower emissions of sulphur and nitrogen oxides.
We have already seen the specifics of acid rain and how it harms wildlife, vegetation, and historical sites. As responsible citizens, we should be aware of the negative effects they cause, as well as the businesses that unethically dispose of nitrogen and sulphur compounds.
The environment is seriously endangered by acid rain. In 1995, the Indian government unveiled an action plan to safeguard the Taj Mahal. The strategy tries to improve the atmosphere in "Taj Trapezium."
The Taj Trapezium is the collective name for the cities of Agra, Mathura, Bharatpur, and Firozabad. This initiative led to the substitution of liquefied petroleum gas or natural gas for coal or oil, in more than 2000 companies located inside the trapezium.
Each and every Indian citizen has a responsibility to preserve the Taj Mahal, an iconic building that represents India.