One of the following is a secondary pollutant

Options

A. DDT
B. PAN
C. Fungicide
D. Herbicide

Answer

To determine which of the following is a secondary pollutant, we can analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understand the Definition of Secondary Pollutants**:
- Secondary pollutants are not directly emitted into the atmosphere. Instead, they form when primary pollutants undergo chemical reactions in the environment.

2. **Evaluate Option 1: DDT**:
- DDT (Dichloro-Diphenyl-Trichloroethane) is a pesticide that is directly released into the environment. Therefore, it is classified as a primary pollutant.
- **Conclusion**: DDT is not a secondary pollutant.

3. **Evaluate Option 2: PAN**:
- PAN (Peroxyacyl Nitrate) is formed when primary pollutants, such as volatile organic compounds (VOCs) and nitrogen oxides (NOx), react in the atmosphere. This makes PAN a secondary pollutant.
- **Conclusion**: PAN is a secondary pollutant.

4. **Evaluate Option 3: Fungicide**:
- Fungicides are chemical compounds used to kill parasitic fungi and their spores. They are applied directly to the environment and are considered primary pollutants.
- **Conclusion**: Fungicides are not secondary pollutants.

5. **Evaluate Option 4: Herbicide**:
- Herbicides are substances used to kill unwanted vegetation. Like fungicides, they are applied directly and are classified as primary pollutants.
- **Conclusion**: Herbicides are not secondary pollutants.

### Final Answer:
The correct answer is **Option 2: PAN**, as it is the only secondary pollutant among the options provided.

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