Exercise solution: Sources of acid rains, Human activities

Question: List two main source of acid rain

Answer. Main sources of acid rain are sulphur oxides (SO2, SO3) and nitrogen oxides (NO, NO2). Sulphur oxides are produced due to reaction of oxygen with sulphur released from power plants and nitrogen oxides are produced due to reaction of oxygen with nitrogen during burning of fossil fuels in automobiles. Acid rain is formed when these oxides from polluted air dissolve in rain water.

Question: List four human activities which contribute to air pollution.

Answer. Four main human activities that contribute to air pollution are:

1. Combustion of fossil fuels from cars and heavy duty motor vehicles.

2. Burning of coal and oil in Power generation plants

3. Incineration of both agricultural and human waste

4. Release of CFCs from household sources (refrigerators, air conditioner, aerosol spray etc)

Question: What is importance of stratospheric ozone?

Answer: Ozone (O3) is an important component of stratosphere. It protects the earth from harmful ultraviolet radiations from the Sun. Ozone absorbs uv radiations and convert these radiations into heat. Without ozone:

i. All UV-radiations would reach the earth and can cause skin cancer in human and animals.

ii. Survival of life on earth is very difficult.

iii. Plants cannot grow.

Question: What is the role of automobile in air pollution?

Answer. Most of air pollution (≈ 50 %) arises from combustion of fossil fuels from automobiles (cars and heavy duty motor vehicles). Carbon monoxide and nitrogen oxides are the main pollutants produced from automobiles. Carbon monoxide is produced due to incomplete burning of fossil fuels. Nitrogen oxides are produced from reaction of oxygen with nitrogen during burning of fossil fuels in automobiles.

Question: Define Atmosphere/

Answer.

The envelop of gases and water vapors surrounding earth planet is known as atmosphere.

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