Loss of chlorophyll and photosynthetic efficiency of plants is reduced by

Options

A. `CO`
B. `CO_(2)`
C. `NO_(2)`
D. PAN

Answer

To answer the question regarding the loss of chlorophyll and the reduction of photosynthetic efficiency in plants, we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which substance leads to the loss of chlorophyll and reduces the photosynthetic efficiency of plants.

2. **Analyzing Option 1: Carbon Monoxide**:
- Carbon monoxide is a gas that can affect atmospheric conditions but does not directly cause the loss of chlorophyll in plants.
- It contributes to greenhouse gas emissions and climate change but is not directly harmful to the chlorophyll content in plants.
- **Conclusion**: This option is incorrect.

3. **Analyzing Option 2: Carbon Dioxide**:
- Carbon dioxide is essential for photosynthesis as it is a key reactant in the process.
- While it is a greenhouse gas, it does not cause the loss of chlorophyll. In fact, it is necessary for plant growth.
- **Conclusion**: This option is incorrect.

4. **Analyzing Option 3: Nitrogen Dioxide**:
- Nitrogen dioxide can have harmful effects on vegetation, but it is not primarily responsible for the loss of chlorophyll.
- It can damage plant foliage and reduce growth, but it does not specifically lead to chlorophyll loss.
- **Conclusion**: This option is incorrect.

5. **Analyzing Option 4: PAN (Peroxyacyl Nitrate)**:
- PAN is a secondary pollutant found in photochemical smog.
- It is known to cause damage to plant tissues, leading to the loss of chlorophyll and a decrease in photosynthetic efficiency.
- This makes PAN the correct answer to the question.
- **Conclusion**: This option is correct.

### Final Answer:
The loss of chlorophyll and the reduction of photosynthetic efficiency in plants is primarily caused by PAN (Peroxyacyl Nitrate).

---