Environmental Issues (Legacy/Detailed)
A detailed exploration of pollution, waste management, and global environmental changes.
Environmental Issues
The human population has grown enormously over the last hundred years. This has led to an increased demand for food, water, home, electricity, roads, and automobiles, exerting tremendous pressure on our natural resources and causing pollution of air, water, and soil.
Air Pollution and Its Control
Air pollution is the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials.
Major Pollutants
- Particulate Matter (PM): Soot, dust, and smoke.
- Gaseous Pollutants: Carbon monoxide (), sulfur dioxide (), nitrogen oxides ().
Control Methods
- Electrostatic Precipitator: Can remove over 99% particulate matter present in the exhaust from a thermal power plant.
- Scrubber: Removes gases like by passing exhaust through a spray of water or lime.
- Catalytic Converters: Fitted into automobiles to reduce emission of poisonous gases. They use expensive metals like platinum-palladium and rhodium as catalysts.
Water Pollution and Its Control
The Government of India has passed the Water (Prevention and Control of Pollution) Act, 1974 to safeguard our water resources.
Key Concepts
- Biochemical Oxygen Demand (BOD): The amount of oxygen required by bacteria to decompose the organic matter in a certain volume of water. High BOD indicates high pollution.
- Algal Bloom: Excessive growth of planktonic algae caused by the presence of large amounts of nutrients in water. It causes deterioration of water quality and fish mortality.
- Biomagnification: Increase in concentration of the toxicant at successive trophic levels.
- Example: Mercury and DDT.
Solid Wastes
Solid wastes refer to everything that goes out in trash.
| Waste Category | Description | Disposal Method |
|---|---|---|
| Biodegradable | Can be broken down by microbes. | Composting, Landfills. |
| Recyclable | Can be processed into new products. | Segregation and Recycling (e.g., Paper, Plastic). |
| Non-biodegradable | Cannot be broken down (e.g., Plastics). | Incineration, Deep burial. |
E-Wastes
Irreparable computers and other electronic goods are known as electronic wastes (e-wastes). Recycling is the only solution for the treatment of e-wastes, provided it is done in an environmentally friendly manner.
Global Environmental Changes
1. Greenhouse Effect and Global Warming
The greenhouse effect is a naturally occurring phenomenon that is responsible for heating of Earth’s surface and atmosphere. Without it, the average temperature at the surface of Earth would have been a chilly -18°C rather than the present average of 15°C.
- Greenhouse Gases (GHGs): CO₂ (60%), CH₄ (20%), CFCs (14%), and N₂O (6%).
2. Ozone Depletion
Ozone in the stratosphere acts as a shield absorbing ultraviolet (UV) radiation from the sun.
- The "Ozone Hole": Thinning of the ozone layer, particularly over the Antarctic region.
- Causes: Chlorofluorocarbons (CFCs) used in refrigerants.
- The Montreal Protocol (1987): An international treaty to control the emission of ozone-depleting substances.
Success Stories in Conservation
Amrita Devi Bishnoi (1731)
Showed extraordinary courage by hugging trees to prevent them from being cut down in Khejarli village, Rajasthan. The Government of India has instituted the Amrita Devi Bishnoi Wildlife Protection Award.
Chipko Movement (1974)
Started in Garhwal Himalayas where local women showed enormous bravery in protecting trees from the axe of contractors by hugging them.
Joint Forest Management (JFM)
The Government of India introduced JFM in the 1980s to work closely with local communities for protecting and managing forests.
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