Which of the following is not a common component of photochemical smog ?

Options

A. Peroxyacetyl nitrate
B. Acrolein
C. Formaldehyde
D. Carbon dioxide

Answer

To solve the question regarding which of the following is not a common component of photochemical smog, we will follow these steps:

### Step 1: Understand Photochemical Smog
Photochemical smog is a type of air pollution that occurs when sunlight reacts with pollutants such as volatile organic compounds (VOCs) and nitrogen oxides (NOx). This reaction leads to the formation of secondary pollutants, including ozone (O3), peroxyacetyl nitrate (PAN), and various aldehydes.

### Step 2: Identify Common Components of Photochemical Smog
Common components of photochemical smog include:
- **Peroxyacetyl Nitrate (PAN)**: A significant component formed from the reaction of nitrogen oxides and organic compounds.
- **Aldehydes**: Such as acrolein and formaldehyde, which are also products of incomplete combustion and are found in smog.
- **Ozone (O3)**: A secondary pollutant formed from the reaction of sunlight with pollutants.

### Step 3: Analyze the Given Options
Now, we will analyze the options provided in the question to identify which one is not a common component of photochemical smog:
- **Option A**: PAN (Peroxyacetyl Nitrate) - Common component.
- **Option B**: Acrolein - Common component (an aldehyde).
- **Option C**: Formaldehyde - Common component (an aldehyde).
- **Option D**: Carbon Dioxide (CO2) - Not a common component of photochemical smog.

### Step 4: Conclusion
Based on the analysis, the correct answer is **D: Carbon Dioxide (CO2)**, as it is not a common component of photochemical smog.

### Final Answer
**D: Carbon Dioxide (CO2)** is not a common component of photochemical smog.

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