Ozone hole is due to:

Options

A. `CO_2`
B. `CO`
C. `CFCs`
D. `SO_2`

Answer

### Step-by-Step Solution:

1. **Understanding the Ozone Layer**: The ozone layer is a region of Earth's stratosphere that contains a high concentration of ozone (O₃) molecules. It plays a crucial role in protecting life on Earth by absorbing the majority of the sun's harmful ultraviolet (UV) radiation.

2. **Identifying the Problem**: The "ozone hole" refers to a significant depletion of the ozone layer, particularly observed over Antarctica. This depletion allows more UV radiation to reach the Earth's surface, which can lead to various environmental and health issues.

3. **Analyzing the Options**: The question provides several options for what causes the ozone hole:
- CO₂ (Carbon Dioxide)
- CO (Carbon Monoxide)
- CFC (Chloro Fluoro Carbons)
- CO₂ (again)

4. **Evaluating Each Option**:
- **CO₂**: While carbon dioxide is a greenhouse gas contributing to global warming, it does not directly cause ozone depletion. Therefore, it is not responsible for the ozone hole.
- **CO**: Carbon monoxide is a pollutant that can affect air quality but does not have a significant impact on the ozone layer. Thus, it is also not responsible for the ozone hole.
- **CFC**: Chloro Fluoro Carbons are synthetic compounds that were commonly used in air conditioning, refrigeration, and aerosol propellants. When CFCs are released into the atmosphere, they eventually reach the stratosphere, where they are broken down by UV radiation, releasing chlorine atoms that react with ozone (O₃) and convert it into oxygen (O₂). This process leads to the depletion of the ozone layer, making CFCs the primary cause of the ozone hole.
- **CO₂ (again)**: As previously mentioned, carbon dioxide does not contribute to ozone depletion.

5. **Conclusion**: The correct answer is CFC (Chloro Fluoro Carbons), as they are the major gases responsible for the depletion of the ozone layer, leading to the formation of the ozone hole.