Environmental Pollution

• The contamination of air, water, and soil by pollutants is called pollution. Environmental pollution degrades the quality of air, water, and soil and makes them unsuitable for use.
• Several human activities are the major causes of pollution.
• Environmental pollution has many ill effects like global warming, acid rain, contamination of water bodies, smog, etc.
• It is necessary to keep a check on environmental pollution for the continuity of life on Earth.

Air Pollution

Question 1:

How Do Toxic Gases Affect Our Bodies?

Answers:

• Toxic gases can damage the cells or tissues of our bodies. Examples of such gases are methane, butane, propane, carbon dioxide in higher amounts, etc.
• These gases, if they enter our body, can lead to the following effects—
• Cancer; can be related to the lungs, skin, kidneys, or bones.
• Respiratory disorders.
• Birth defects in pregnant women.

Question 2:

How Is Ozone Layer Depletion Related to Skin Cancer?

Answers:

• A layer of ozone gas in the atmosphere protects us from the sun's harmful UV rays.
• However, the ozone layer is affected by the gases released due to air pollution. These gases have created holes in this layer, allowing UV rays to reach the Earth's surface.
• If any part of our body remains exposed to these UV rays for a long time it may lead to skin cancer.

Question 3:

Write the Differences Between Renewable and Non-Renewable Sources of Energy.

Answers:

The differences between renewable and non-renewable sources of energy are as follows—

Renewable Sources	Non-renewable Sources
Renewable sources of energy will not get depleted over time.	Non-renewable sources of energy will be depleted over time.
These sources cause less or no pollution at all.	These sources lead to environmental pollution.
Examples: Wind energy, solar energy, etc.	Examples: Coal, natural gas, and petroleum

Question 4:

What Is Greenhouse Effect?

Answers:

• The atmosphere surrounding the Earth is a mixture of gases. Among these gases, carbon dioxide The atmosphere surrounding the Earth is a mixture of gases. Among these gases, carbon dioxide and methane can absorb the sun's heat.
• As a result, the Earth remains warm, which is essential for the sustenance of life.
• The greenhouse effect is trapping the sun's heat in the Earth's atmosphere due to these gases.

Question 5:

Why Are We Advised To Minimise the Usage of Deodorants?

Answers:

• Deodorants emit a specific type of compound called chlorofluorocarbons into the environment.
• These compounds are air pollutants and cause depletion of the ozone layer.

Water Pollution

Question 1:

How Do Pesticides and Herbicides Cause Water Pollution?

Answers:

• Farmers apply pesticides and herbicides to protect crops from diseases and kill pests and unwanted vegetation.
• The toxic chemicals in these compounds seep into water sources like rivers or lakes through irrigation water and cause water pollution.

Question 2:

How Is Wastewater Treated in Water Treatment Plants?

Answers:

The following steps are followed for wastewater treatment in the water treatment plants—

Question 3:

What is Biomagnification?

Answers:

• Biomagnification stands for the accumulation of toxic materials in the bodies of organisms at each level of a food chain.
• These toxic materials do not degrade and pass from one organism to another.
• The concentration of toxic materials increases with an increase in the food chain level.

Sound Pollution

Question 1:

How Do Movie Theatres Are Made Soundproof?

Answers:

The walls of movie theatres are insulated with an additional covering of fibreglass and foam, which absorbs 80% of the sound waves and does not allow them to be heard outside the theatres.