Pollution (Part-II)

Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOx) are emitted into the atmosphere and transported by wind and air currents. The SO2 and NOx react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground.

While a small portion of the SO2 and NOx that cause acid rain is from natural sources such as volcanoes, most of it comes from the burning of fossil fuels. The major sources of SO2 and NOx in the atmosphere are:

• Burning of fossil fuels to generate electricity. Two thirds of SO2 and one fourth of NOx in the atmosphere come from electric power generators.

• Vehicles and heavy equipment.

• Manufacturing, oil refineries and other industries.

Acidity and alkalinity are measured using a pH scale for which 7.0 is neutral. The lower a substance's pH (less than 7), the more acidic it is; the higher a substance's pH (greater than 7), the more alkaline it is.

*Significantly normalluy rain water has a pH of 5.6 due to the presence of H. ions. When the pH of the rain water drops below 5.6, itis called acid rain. Notably Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth's surface.

Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOx) are emitted into the atmosphere and transported by wind and air currents. The SO2 and NOx react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground.

While a small portion of the SO2 and NOx that cause acid rain is from natural sources such as volcanoes, most of it comes from the burning of fossil fuels. The major sources of SO2 and NOx in the atmosphere are:

• Burning of fossil fuels to generate electricity. Two thirds of SO2 and one fourth of NOx in the atmosphere come from electric power generators.

• Vehicles and heavy equipment.

• Manufacturing, oil refineries and other industries.

Acidity and alkalinity are measured using a pH scale for which 7.0 is neutral. The lower a substance's pH (less than 7), the more acidic it is; the higher a substance's pH (greater than 7), the more alkaline it is.

*Significantly normalluy rain water has a pH of 5.6 due to the presence of H. ions. When the pH of the rain water drops below 5.6, itis called acid rain. Notably Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth's surface.

Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOx) are emitted into the atmosphere and transported by wind and air currents. The SO2 and NOx react with water, oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water and other materials before falling to the ground.

While a small portion of the SO2 and NOx that cause acid rain is from natural sources such as volcanoes, most of it comes from the burning of fossil fuels. The major sources of SO2 and NOx in the atmosphere are:

• Burning of fossil fuels to generate electricity. Two thirds of SO2 and one fourth of NOx in the atmosphere come from electric power generators.

• Vehicles and heavy equipment.

• Manufacturing, oil refineries and other industries.

Acidity and alkalinity are measured using a pH scale for which 7.0 is neutral. The lower a substance's pH (less than 7), the more acidic it is; the higher a substance's pH (greater than 7), the more alkaline it is.

*Significantly normalluy rain water has a pH of 5.6 due to the presence of H. ions. When the pH of the rain water drops below 5.6, itis called acid rain. Notably Acid rain refers to the ways in which acid from the atmosphere is deposited on the earth's surface.

While a small portion of the SO2 and NOX that cause acid rain is from natural sources such as volcanoes, most of it comes from the burning of fossil fuels. The major sources of SO2 and NOX in the atmosphere are:

• Burning of fossil fuels to generate electricity. Two thirds of SO2 and one fourth of NOX in the atmosphere come from electric power generators.

• Vehicles and heavy equipment.

• Manufacturing, oil refineries and other industries.

Effects of Acid Rain on Fish and Wildlife

The ecological effects of acid rain are most clearly seen in aquatic environments, such as streams, lakes, and marshes where it can be harmful to fish and other wildlife. As it flows through the soil, acidic rain water can leach aluminum from soil clay particles and then flow into streams and lakes. The more acid that is introduced to the ecosystem, the more aluminum is released.

Effects of Acid Rain on Plants and Trees

At high elevations, acidic fog and clouds might strip nutrients from trees' foliage, leaving them with brown or dead leaves and needles. The trees are then less able to absorb sunlight, which makes them weak and less able to withstand freezing temperatures.

Effects of Acid Rain on Materials

Not all acidic deposition is wet. Sometimes dust particles can become acidic as well, and this is called dry deposition. When acid rain and dry acidic particles fall to earth, the nitric and sulfuric acid that make the particles acidic can land on statues, buildings, and other manmade structures, and damage their surfaces. The acidic particles corrode metal and cause paint and stone to deteriorate more quickly. They also dirty the surfaces of buildings and other structures such as monuments.

Human Health

Walking in acid rain, or even swimming in a lake affected by acid rain, is no more dangerous to humans than walking in normal rain or swimming in non-acidic lakes. However, when the pollutants that cause acid rain -SO₂ and NOX, as well as sulfate and nitrate particles are in the air, they can be harmful to humans.

SO₂ and NOX react in the atmosphere to form fine sulfate and nitrate particles that people can inhale into their lungs.