What Is Acid Rain? | Causes And Effects
- A mixture of wet and dry deposition (deposited material) from the atmosphere containing higher than normal amounts of nitric and sulfuric acids is referred to as "acid rain."
- Precursors, or chemical forerunners, of acid rain formation come from both natural and man-made sources, primarily Sulphur dioxide (SO2) and nitrogen oxide (NOx) emissions from fossil fuel combustion.
- Acid rain occurs when these gases react with water, oxygen, and other chemicals in the atmosphere to produce various acidic compounds. The result is a mild sulfuric acid and nitric acid solution.
CAUSES OF ACID RAIN
- The causes of acid rain are sulfur and nitrogen particles that mix with the wet components of rain. These particles are found in two ways: either man-made, such as emissions from industries, or by natural causes, such as lightning strikes in the atmosphere releasing nitrogen oxides and volcanic eruptions releasing sulfur oxide.
- According to the Royal Society of Chemistry, the word "acid rain" was invented in 1852 by Scottish chemist Robert Angus Smith, who is considered the "father of acid rain." Smith decided on the word while studying rainwater chemistry near industrial towns in England and Scotland.
- The regular rain we experience, even though it is not clean, is not extremely harmful as it is water and carbon dioxide reacting together to form weak carbonic acid. The reaction occurring is:
H2O (l) + CO2 (g) ⇌ H2CO3 (aq)
The pH value of regular rainwater is around 5.7, giving it an acidic nature. The oxides of nitrogen and sulfur 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 that emit oxides of nitrogen and sulfur into the atmosphere, for example, the burning of fossil fuels and unethical waste emission disposal techniques.
Acid rain forms when sulfur dioxide and nitrogen dioxide undergo oxidation and then react with water, resulting in the formation of sulfuric acid and nitric acid, respectively. The following reaction will clarify the acid formation reaction:
2SO2 (g) + O2 (g) + 2H2O (l) → 2H2SO4 (aq)
4NO2 (g) + O2 (g) + 2H2O (l) → 4HNO3 (aq)
EFFECTS OF ACID RAIN
- Acid rain contributes to the damage of trees at high elevations (for example, red spruce trees above 2,000 feet) and many sensitive forest soils by acidifying lakes and streams.
- Acid rain also hastens the deterioration of building materials and paints, including irreplaceable structures, statues, and sculptures that are part of our country's cultural heritage.
- Sulfur dioxide (SO2) and nitrogen oxide (NOx) gases, as well as their particulate matter derivatives—sulfates and nitrates—degrade visibility and harm public health before they fall to the ground.
PREVENTIVE MEASURES
- Acid rain, or acid deposition, can be reduced in a variety of ways, ranging from societal changes to individual action.
- To preserve the integrity of natural habitats and to reduce damage to man-made structures, acid deposition must be reduced not only in India but also around the world.
- Clean smokestacks and exhaust pipes regularly.
- Make use of alternative energy sources.
- Acidic lakes can be treated with limestone or lime (a naturally occurring basic compound) to neutralize the acidity.
- Purchase vehicles with low NOx emissions and maintain them properly.