Photochemical smog occurs in warm, dry and sunny climate, One of the following is not amongst the components of photochemical smog, identify it.

Options

A. `NO_(2)`
B. `O_(3)`
C. `SO_(2)`
D. Unsaturated hydrocarbon

Explanation

To identify which component is not part of photochemical smog, we need to understand what photochemical smog consists of and the conditions under which it forms.

### Step-by-Step Solution:

1. **Understanding Photochemical Smog**:
Photochemical smog is a type of air pollution that occurs in warm, dry, and sunny climates. It is primarily formed through photochemical reactions involving sunlight.

**Hint**: Remember that photochemical smog is associated with sunlight and specific chemical reactions.

2. **Components of Photochemical Smog**:
The main components of photochemical smog include:
- Unsaturated hydrocarbons (which react in the presence of sunlight)
- Nitrogen dioxide (NO2)
- Ozone (O3)
- Peroxyacyl nitrate (PAN)
- Aldehydes and ketones (produced from the oxidation of hydrocarbons)

**Hint**: List the common components of photochemical smog to identify the outlier.

3. **Identifying the Outlier**:
Now, we need to identify which of the following options is NOT a component of photochemical smog:
- NO2 (Nitrogen dioxide)
- O3 (Ozone)
- SO2 (Sulfur dioxide)
- Unsaturated hydrocarbons

From our understanding, NO2, O3, and unsaturated hydrocarbons are indeed part of photochemical smog. However, sulfur dioxide (SO2) is typically associated with industrial pollution and is not a primary component of photochemical smog.

**Hint**: Compare each option against the known components of photochemical smog.

4. **Conclusion**:
Therefore, the component that is NOT part of photochemical smog is **SO2 (Sulfur dioxide)**.

**Final Answer**: SO2 is not amongst the components of photochemical smog.