Acid Rain: anathema to the pluviophile – Erakina

Looking at the rains, pouring down the skies,  never fails to remind me of the verse of William Wordsworth :

How beautiful is the rain!

After the dust and heat,

In the broad and fiery street,

In the narrow lane,

How beautiful is the rain!!….

Alt: Rain droplets on a clear umbrella.
The pouring rain fills in new colors around, bringing life to all.

But today rains may not be as joyful and valuable as they used to be. Today’s rain might burn your plants or ruin your monuments…!!.. Don’t be surprised if you are new to this statement because rainwater today is not the purest form of water as defined in our Environmental education books. 

Pollution has become a curse for humanity along with the elements of the earth. Well, nothing shocking that we only are responsible for it. Acid rain is the outcome of the incessantly increasing air pollution. 

Here is a glance at how we are jeopardizing our future generations’ boat steering experiences in the rain puddles….

What is Acid Rain?

Acid rain is defined as the several ways in which acids from the atmosphere are deposited in the earth in the forms of oxides of Nitrogen and Sulphur. It can also occur in the form of snow, fog, and tiny bits of dry material that settle on Earth.

It is caused by pollutants like Sulphur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce concentrated hydro sulphuric acid and nitric acid respectively. 

The word ‘Acid Rain’ was first conceived by Robert Angus Smith in 1872. First-time acid rain was noticed in Sweden in 1972 but Norway and Canada have been badly affected..!!..

Since the onset of the Industrial Revolution, emissions of Sulphur and nitrogen oxides have intensified leaps and bounds. The corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn. 

Industries during the Industrial Revolution.
Industrial Revolution in the 17th century, initiated emissions of toxic gases.

The pH of acid rain is low ranging from an average of 4-5, pH curtails as acidity increases. Acid rain can have harmful effects on plants, aquatic animals, and infrastructure causing the paint to peel, corrosion of steel structures, and weathering of stone buildings and statues as well as having impacts on human health.

Causes of Acid Rain

70 Tg per year in the form of Sulphur Dioxide comes from fossil fuel combustion and industry, 2.8 Tg from wildfires, and 7–8 Tg per year from volcanoes.

The various causes of acid rain can be broadly classified as follows :

  1. Natural Causes
  2. Man-made Causes

Natural Causes 

The prominent natural phenomena which contribute to acid-producing gases to the atmosphere are Volcanic Eruptions.

  • Volcanoes produce large amounts of Sulphur dioxide.
    • Example: The fumaroles from the Laguna Caliente crater of Poás Volcano create extremely high amounts of acid rain and fog, with acidity as high as a pH of 2, clearing an area of any vegetation and frequently inducing irritation to the eyes and lungs of inhabitants in nearby colonies.
A volcano erupting gases at its full vigour.
The gases produced by an erupting volcano add to acid rain.
  • Acid-producing gasses are produced by the biological processes occurring on the land, in wetlands and the oceans. 
  • Lightning is a natural producer of Nitric Acid. The electrical activities during lightning spur the production of nitric acid.
  • Soils of coniferous forests are naturally very acidic due to the shedding of needles, but it’s not a confirmed cause of acid rain.

Man-Made Causes

Various advancement activities oh humans cause the production of Sulphur and nitrogen compounds such as, 

  • Generation of Electricity– Usage of coal in the process of electricity production contributes to gaseous pollution leading to acid rain. 
  • Animal Agriculture
  • Increase in Automobiles– The burning of petrol, diesel produces harmful gases which add to the air pollution.
A car without a catalytic converter producing smoke.
Harmful gases are produced by the combustion of fuels
  • Expansion of industries
A great amount of harmful smoke is erupted by industries and factories.
Increasing expansion of industries has worsened the acid level in rains.
  • Burning of fossil fuels– Combustion of coal, gas and wood adds up to increase the level of oxides of Sulphur and nitrogen.

Why is Acid Rain harmful?

Now it’s a question of utter curiosity as to why acid rain is so detrimental… It would have been a relief if the acids did not deposit over. But, the unfortunate aspect is that Acids deposit over soils, infrastructure and monuments; while degrading them. 

The various impacts of Acid Rain over different elements of the Earth are as follows:


  • Acid rains damage the soil biology and chemical balance leading to Soil Acidification.
  • The acids kill the intrinsic microbes in the soil due to sudden changes in pH.
  • The enzymes of these microbes are denatured by the acids.
  • Acidic water and soil acidification cause plants to get their minerals blocked,  resulting in their death.
  • Acid rain falling on plant leaves causes drying of the waxy leaf cuticle, which ultimately causes rapid water loss from the plant.

Vegetation and Forests

    • High altitude forests are vulnerable as they are often surrounded by clouds and fog which are more acidic than rain.
    • In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands
  • Example – In the Red Spruce, when calcium is leached from its needles, these trees become less cold tolerant and exhibit winter injury and even demise.

Surface Waters and Aquaculture 

  • Acid rain lowers the pH and raises the aluminium concentration in the surface waters which causes damage to fish and marine animals.
  • Acidic lakes and rivers have reduced biodiversity.
  • Acid rain has eliminated insect life and some fish species.

Ocean acidification

  • Acid rain can cause the ocean’s pH to fall, making it more difficult for different coastal species to create the exoskeletons that they need to survive.
  • The calcium carbonate of Coral’s limestone skeleton dissolves in low pH acidic water.
Beautiful brown and black coral reefs underwater.
Damage to coral reefs due to acidic water has led them towards extinction.
  • Excess nitrogen inputs from the atmosphere promote increased growth of phytoplankton and other marine plants, which, in turn, may cause more frequent harmful algal blooms and eutrophication.

Human health 

  • Acid rain does not have an immediate effect on human health, as the acid is too dilute to have a direct effect.
  • Increased amounts of fine particulate matter in the air contribute to heart and lung problems, including asthma and bronchitis.

Sculptures and Infrastructure 

  • Acid rain damages buildings, historic monuments, and statues, especially those made of rocks, such as limestone and marble, containing large amounts of calcium carbonate. 
A gargoyle being reduced to flakes due to acid rain.
Acids in rainwater flake off the calcium carbonate to gypsum, which gets eroded.
  • Acids in the rain react with the calcium compounds in the stones to create gypsum, which then flakes off.
  • Acid rain also increases the corrosion rate of metals, such as iron, steel, copper and bronze.

Adversely affected examples around the world

There are various examples of adversely affected places, monuments, buildings, lakes, living entities in the world. Some of the prominent ones are discussed here : 

  • Acid rain caused the death of biota of lakes in North-west Europe and Canada. Therefore it’s known as ‘Lake Killer’.
  • In India, acid rain is responsible for the corrosion of monuments like the Taj Mahal, a Wonder of the World. 

The emission of Sulphur dioxide from Mathura Oil Refinery has caused the marble of the Taj to change its color and corrosion of Taj.

The 7th wonder of the world, The Taj Mahal.
The Mathura oil refinery is killing the marble of the Taj.
  • The 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 Statue of Liberty in New York is a masterpiece.
It’s an original copper color, but now we recognize it in green. Thanks to acid rain..!!
  • Acid rain has eliminated some insect, fish species including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States

We just cannot afford to see our lakes, rivers, plants, living beings and monuments getting withered off and damaged. It’s not the time to sit and watch…!!..

What to do and what’s being done?

The main area to be worked upon is Air Pollution. Air needs to be safeguarded from being contaminated.

Believe me, nobody wants the World of Wonders to be corrupted or the lakes to be dead or oceans to get acidified or corals to be lost. Our environmentalists are working day and night just to save the earth by all means. 

Awareness dance party organized against acid rain in 1989.
An initiative interestingly taken against acid rain.

But we as residents of the blue planet need to know what to do at our ends to save it. It’s our responsibility, not the aliens…. Let’s see what joining of little hands can lead to:-

    • The Flue gas desulfurization technique is being established by many coal-firing power stations, to remove Sulphur-containing gases from their stack gases. 
  • Example: Wet Scrubbers are a reaction tower equipped with a fan that extracts hot smokestack gases from a power plant into the tower. 
  • In some areas, the sulphates are sold to chemical companies as gypsum when the purity of calcium sulphate is high. In others, they are placed in landfills.
  • Vehicle emissions can be controlled by replacing petrol, diesel and CNG with Bio-diesel, P-series fuel and Solar fuels. They have low-Sulphur content and serve as alternative fuel options.

Policy measures to curb air pollution 

  1. The 1985 Helsinki Protocol on the Reduction of Sulphur Emissions under the Convention on Long-Range Transboundary Air Pollution, by European countries.
  2. Air Quality Agreement between Canada and USA in 1991.
  3. In 2000, a foreign coalition to prevent acid rain was sparked in Asia for the first time.
  4. The first Emissions trading market was established in the United States by the enactment of the Clean Air Act Amendments in 1990.
  5. National Air Quality Monitoring Programme of India
  6. Bharat Norms or Euro Norma was started on June 1, 1999.

Being responsible citizens, we all must come together and work unified in the current times to leave a healthy, beautiful future for the successive generations to live.

So hold hands and pledge

It’s high time that we all stop ourselves from deteriorating the environment, the earth and our Nature. We must not take undue advantage of the benevolence of Mother Nature because nothing will save us if she starts punishing us. 

The 2020 pandemic has put all the humans behind the doors, the floods spare no one, the earthquake lava burns everything; all this means that nature won’t spare anyone if it flares up. Do not twist till it breaks….

As earthlings, we all have certain duties towards the planet we reside on. The fossil fuels we burn are coming back to haunt us only. I know it’s not a one day magic but a long procedure. But we can’t expect any changes if we don’t begin now.

A poetic start demands a poetic ending too. So one last message for you all in the words of  Michael Jackson: 

“Heal the world…make it a better place, for you and for me and the entire human race….!!!.”.

– by Sambhavi Yadav

Content Writer (Erakina by RTMN)


Tags: Acid rain, climate change, Rain flooding

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