Causes and effects of acid rain

Definition of acid rain in simple words

Acidic components, such as sulfuric, nitric or hydrochloric acid dissolved in rainwater that falls to the ground from the atmosphere in wet or dry formed is called acid rain. Thus acid rain causes by the emission of SOx and NOx from different sources and effects our environment.

Natural rain-water is slightly acidic (pH scale = 5.6) because it contains some atmospheric CO2 that forms carbonic acid when reacts with water. But if pH scale for this water 5.6 to 3.5 and falls as rain, snow, fog or dust.

CO2 + H2O → H3CO3

How is acid rain formed and its causes effects?
Causes and effects of acid rain

How acid rain formed?

SO2 is a major pollutant of our environment. SO2 released by burning oil and coal, which discharged by industries causes damage to our plant and animal life. About 200 million tonnes of this gas released over the world from industries and equal amounts released by natural processes.

SOx to H2SO4 in atmosphere

SO2 partially oxidized to SO3 in the air by a photolytic or catalytic process initiated by ozone, hydrocarbons, nitrogen oxides, and soot or dust. The SO3 gives rises to H2SO4 with water causing acid rain.

    \[ 2SO_{3}+O_{2}\xrightarrow{photolytic\, ray\, 300-400nm}2SO_{3} \]

    \[ SO_{2}+O_{3}\rightarrow SO_{3}+O_{2} \]

    \[ SO_{2}+O_{3}\rightarrow SO_{3}+O_{2} \]

    \[ SO_{3}+H_{2}O\rightarrow H_{2}SO_{4}} \]

    \[ SO_{2}+\frac{1}{2}O_{2}+H_{2}O\xrightarrow{CuO,FeO,MnO}H_{2}SO_{4} \]

Formation of HNO3 from NOx

2NO + O2 → 2NO2
NO + O3 → NO2 + O2
NO2 + NO3 → N2O5

N2O5 + H2O → 2HN03

Effects of acid rain on plants and animals

  1. Acid rain effects the acidity of the soil, which changes the solubility of the different metal salt mainly aluminum salt in the soil. Thus some microbes unable to tolerate such changes and killed which decreases the fertility of the soil.
  2. The effects of this rain are clearly seen in the fish and aquatic life of our environment. The pH of Most of the lakes is between 6 to 8 but some lakes are naturally acidic. Thus with the increasing acidity of the water fertility of fishes decreases and young fishes are dying. It also affects aquatic animals.
  3. It does not affect humans directly. Many dangerous metals particles are dissolved in water through this rain. When we drink such water, it transported to our body which affects our lungs. It also affects our skin, shell and neuronal system of our body.
  4. Acid rain causes damages marble made buildings, bridges, statues, monuments, tombstones, and other cultural artifacts. Because H2SO4 reacts with marble (CaSO4) to produce a layer of CaSO4 which can decrease the brightness of cultural artifacts.

CaCO3 + H2SO4 → CaSO4↓ + CO2↑ + H2O

Scientific technology solution

  1. Increasing the use of atomic energy, wind, and solar energy, hydroelectric power for the source of electricity.
  2. Using requisite technology for reducing the emission of NOx and SOx from the thermal power plant or different production factory.
  3. Decreasing the use of fossil fuel in our daily life.
  4. Using technology in vehicles for reducing the emission of NOx.