HOW DOES OUR ACTIVITY AFFECT THE ENVIRONMENT?
Ozone Layer and Its Depletion
- Ozone (O3) is a deadly poison. However, at higher levels of the atmosphere, ozone shields the Earth's surface from dangerous ultraviolet (UV) radiation from the Sun. UV radiation causes harmful effects such as skin cancer.
- At higher levels of the atmosphere, higher-energy UV radiation splits some O2 into free oxygen (O) atoms, which combine with O2 to form ozone (O3).
- In the 1980s, the amount of ozone began to drop sharply due to chemicals like chlorofluorocarbons (CFCs), which are used as refrigerants and in fire extinguishers.
- In 1987, the United Nations Environment Programme (UNEP) made an agreement to freeze CFC production at 1986 levels. It is now mandatory to make CFC-free refrigerators.
- Other ozone-depleting substances: Hydrofluorocarbons (HFCs), halons, etc.
- The size of the ozone hole has increased in recent years.
Managing the Garbage We Produce
- Garbage is unwanted material that people have thrown away.
- In organisms, specific nutrients are needed to break down a particular substance. Similarly, bacteria or other saprophytes have no enzymes to break down artificial materials like plastics.
- Substances that are broken down by biological processes are called biodegradable, e.g., fruits, vegetables, leaves, meat, paper, rubber, etc.
- Substances that are not broken down by biological processes are called non-biodegradable. They are inert, and persist for a long time, or may harm the ecosystem, e.g., plastics, glass, nylon, etc.
| Non-biodegradable Substances | Average Time to Break Down |
|---|---|
| Glass Bottle | - |
| Plastic Bags | 10-20 years |
| Plastic Container | 50-80 years |
| Plastic Soda Bottle | 12 years |
| Nylon Fabric | 30-40 years |
- There are biodegradable plastics such as Polylactic acid, Polyhydroxyalkanoates, Polybutylene succinate, etc.
- At home and in the classroom, various biodegradable and non-biodegradable wastes are produced. They have to be collected separately and treated properly.
- The local body (panchayat, municipal corporation, resident welfare association) has mechanisms to treat biodegradable and non-biodegradable wastes separately.
- Improvements in lifestyle and changes in attitude have generated a large amount of waste material.
- Changes in packaging have resulted in much of our waste becoming non-biodegradable.
Disposable cups in trains:
Disposable plastic cups are non-biodegradable. An alternative was kulhads (disposable clay cups). But making these results in the loss of fertile topsoil. Now disposable paper cups are used, which are better than plastic cups because they are biodegradable and do not affect the properties of drinks in the cup.
Electronic & electrical wastes (e-wastes):
- Include mobile phones, computers, televisions, etc.
- They contain dangerous chemicals such as mercury, lead, cadmium, polybrominated flame retardants, barium, and lithium. They cause damage to the brain, heart, liver, kidney, and skeletal system.