What is acid rain?
Acid rain or acid deposition is the major pollutants of our environment form by the precipitation of acidic components like sulfur trioxide or nitric oxide. Nitric acid or sulfuric acid rain comes down in the environment by raindrop, snow, fog, hail, or even dust. Acid rain has adverse impacts on plants, aquatic life, soil, and archeological specimens like bridges, stone buildings, and statues of our environment. It causes soil and water pollution by acid deposition. Therefore, we need to find scientific solutions to minimize the effect caused by acid rain or acid deposition
How is acid rain formed?
It is formed mainly by the emission of SOx and NOx from different types of sources like coal, oils or automobile engine burning, etc. Natural rainwater is also slightly acidic (pH scale = 5.6) because it contains some atmospheric carbon dioxide. It reacts with water to form the carbonic acid solution.
How is sulfur dioxide formed?
Sulfur dioxide and nitrogen dioxide are the major pollutants of our environment that cause air, water, and soil pollution. Sulfur dioxide is released by burning oil, coal, and industry reacts with rainwater to form sulfuric acid. It damages the plant, animal, and humans life of our environment. About 200 million tonnes of sulfur dioxide are released over the world from different types of industries. Equal amounts of SO2 are released by different types of natural processes.
How is sulfuric acid rain formed?
Sulfur dioxide is partial oxidation to form sulfur trioxide in the air by the photolytic or catalytic process initiated by ozone gas, hydrocarbon, nitrogen oxides, and soot or dust. This sulfur trioxide reacts with rainwater or moisture gives sulfuric acid. This acid comes down the atmosphere in the form of sulfuric acid rain or acid snow. It causes mainly water pollution and soil pollution.
|2SO3 + O2 → 2SO3|
|SO2 + O3 → SO3 + O2|
|SO3 + H2O → H2SO4|
Nitric acid rain
Source of nitrogen dioxide
The smoke released by the automobiles engines contains nitrogen dioxide that causes acid rain and greenhouse effect. This smoke is obtained by the thermodynamic combustion of petrol or diesel in different types of engines. Many chemical plants like explosives or nitrogenous fertilizers production plants produce nitrogen dioxide. Large amounts of sulfur or nitrogen dioxide are also emitted from power plants and many industrial processes. These mixtures of gases contain sulfur dioxide or nitrogen dioxide It is called flue gases.
Formation of nitric acid rain
The nitrogen dioxide produces from the above sources reacts with the rainwater or moisture in the presence of oxygen or ozone to form nitric acid rain or snow.
|2NO + O2 → 2NO2|
|NO + O3 → NO2 + O2|
|NO2 + NO3 → N2O5|
|N2O5 + H2O → 2HNO3|
Effects of acid rain on the environment
It serves many harmful impacts on our environment to the animal, plant, and fish life.
- Acid rain has served ecological impacts. It gradually eating up the limestone and marble of the bridges, buildings, statues, monuments, tombstones, and other cultural artifacts.
- Due to their corrosive nature, these pollutants decolorize building materials like limestone, marble, roof slate, and metals.
- Fabrics, leather, paper, and paints undergo fading of their color in the presence of SO2 and NO2.
- The negative effect of acid deposition increases the acidity of the soil and lakes water. This changes the solubility of the different metal elements salt in soil mainly the aluminum salt in the soil.
- The effects of acid rain are seen in the fish, plants, and humans life of our environment. With the increasing acidity of the water, the fertility of fishes decreases, or young fishes are dying.
Effects of acid rain on humans
- It can not affect or harm humans directly. It increases the concentration of many dangerous metals or particles through acidic water. When we drink such water, it is transported to our body which effects our lungs and kidney.
- It also makes the lakes so acidic that they can no longer support drinking or bathing.
- The formation of acid rain reduces the formation of agricultural crops which we used in our daily life.
- The nitrogen dioxide which creates acid rain promotes the formation of ground-level ozone gas. It causes lung problems for human beings. It also effects our skin, cells, and the neuronal system of our body.
How to reduce nitrogen dioxide emissions?
Nitrogen dioxide can be controlled by reducing with air in the presence of the platinum catalyst produces nitrogen and ammonia molecule. Therefore, before this enters the atmosphere this process may be applied.
How is sulfur dioxide removed from the atmosphere?
The density of sulfur dioxide decreases by treating the flue gases with the slurry of calcium carbonate which absorbed the SO2 gases due to the formation of CaSO3. But the process is quite economical. SO2 may also be reduced partially by desulphurization of coal and Naptha or using natural gas in place of coal. But this technical information for the solutions of acid deposition facts not fully utilizes in practice due to many causes.
Solutions of acid rain
- For the solution of acid rain, increasing the use of renewable energy like wind, and solar energy, hydroelectric energy unit for the source of electricity.
- Using requisite technology for reducing the emission of NOx and SOx from the thermal power plant or different production factories.
- Decreasing the use of fossil fuel in our daily life to decreasing this type of pollution.
- Using technology in vehicles for reducing the emission of NOx. Therefore, modern technology uses in vehicle or thermal power plants reduces the harmful effect of acid rain, snow.