Which of these components present in air is a pollutant?

Options

A. Oxygen
B. Carbon dioxide
C. Water vapour
D. Sulphur dioxide

Answer

To determine which component present in air is a pollutant, we can follow these steps:

### Step 1: Identify the Components of Air
Air is composed of various gases, primarily:
- Nitrogen (78%)
- Oxygen (21%)
- Carbon Dioxide (0.03%)
- Water Vapor (variable percentage)
- Other gases (less than 1%)

### Step 2: Analyze Each Component
- **Oxygen (O2)**: This gas is essential for life and is not considered a pollutant.
- **Carbon Dioxide (CO2)**: While it is a greenhouse gas and can contribute to global warming, it is also a natural part of the air and is essential for photosynthesis in plants. Thus, it is not classified as a pollutant in normal concentrations.
- **Water Vapor (H2O)**: This is a natural component of air and is not considered a pollutant.
- **Sulfur Dioxide (SO2)**: This gas is produced from burning fossil fuels and is known to cause air pollution and respiratory problems. It is classified as a pollutant.

### Step 3: Conclusion
Among the components listed, **sulfur dioxide (SO2)** is the pollutant.

### Final Answer
The component present in air that is a pollutant is **sulfur dioxide (SO2)**.

---