Pollutant that reduces `O_(2)`-carrying capacity of blood is

Options

A. `SO_(2)`
B. CO
C. `CO_(2)`
D. None of the above

Answer

To solve the question regarding which pollutant reduces the oxygen-carrying capacity of blood, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Pollutants**: The options provided are SO2 (sulfur dioxide), CO (carbon monoxide), CO2 (carbon dioxide), and none of the above.

2. **Understand the Function of Hemoglobin**: Hemoglobin is the protein in red blood cells responsible for transporting oxygen. It binds to oxygen in the lungs and releases it in tissues.

3. **Analyze Each Option**:
- **SO2 (Sulfur Dioxide)**: While it is a harmful pollutant, it does not directly affect the oxygen-carrying capacity of hemoglobin.
- **CO (Carbon Monoxide)**: This is a colorless, odorless gas that binds to hemoglobin much more effectively than oxygen does. When CO binds to hemoglobin, it forms carboxyhemoglobin, which reduces the amount of hemoglobin available to carry oxygen.
- **CO2 (Carbon Dioxide)**: This is a natural component of the blood and is not a pollutant that reduces oxygen-carrying capacity; in fact, it is a byproduct of cellular respiration.
- **None of the Above**: This option is incorrect since we have identified a pollutant that does affect oxygen carrying capacity.

4. **Conclusion**: Based on the analysis, the pollutant that reduces the oxygen-carrying capacity of blood is **CO (Carbon Monoxide)**.

### Final Answer:
The pollutant that reduces the oxygen-carrying capacity of blood is **CO (Carbon Monoxide)**.

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