Mark the correct statement (w.r.t. photochemical smog)

Options

A. Also called classical smog
B. Formed in traffic congested cities where warm condition and intense solar radiation are present
C. Secondary pollutant and has no effect on vegetations
D. Occurs at low temperature and contains `H_(2)S` and `SO_(2)`

Answer

### Step-by-Step Solution:

1. **Understanding Photochemical Smog**:
- Photochemical smog is a type of air pollution that occurs in urban areas, particularly in warm, sunny conditions. It is characterized by the presence of secondary pollutants formed through photochemical reactions.

2. **Identifying Characteristics**:
- Photochemical smog is often referred to as "Los Angeles smog" because it was first identified in Los Angeles in the 1940s. It typically appears as a grayish or yellowish-brown haze.

3. **Conditions for Formation**:
- This type of smog forms in conditions of high temperature and intense solar radiation, which are prevalent in traffic-congested cities.

4. **Composition of Photochemical Smog**:
- Photochemical smog contains secondary pollutants, such as nitrogen oxides (NOx) and ozone (O3), rather than primary pollutants like sulfur dioxide (SO2) or hydrogen sulfide (H2S).

5. **Effects on Vegetation**:
- Photochemical smog has detrimental effects on vegetation, particularly affecting the chloroplasts in plants, which can hinder photosynthesis.

6. **Evaluating the Given Statements**:
- **Statement 1**: "Also called classical smog" - Incorrect, as photochemical smog is different from classical smog.
- **Statement 2**: "Formed in traffic congested cities where warm conditions and intense solar radiation are present" - Correct.
- **Statement 3**: "Secondary pollutant and has no effect on vegetation" - Incorrect, as it does affect vegetation.
- **Statement 4**: "Occurs at low temperature" - Incorrect, as it occurs at high temperatures.
- **Statement 5**: "Contains H2S and SO2" - Incorrect, as it primarily contains nitrogen oxides and ozone.

7. **Conclusion**:
- The correct statement regarding photochemical smog is the second one: "Formed in traffic congested cities where warm conditions and intense solar radiation are present."

### Final Answer:
- The correct statement is: **"Formed in traffic congested cities where warm conditions and intense solar radiation are present."**

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