Which is the greatest air pollutant these days?

Options

A. Factories
B. Motor vehicles
C. Domestic appliances
D. Animals

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for the greatest air pollutant these days among the given options: factories, motor vehicles, domestic appliances, and animals.

2. **Analyze Each Option**:
- **Factories**: Factories do emit pollutants like nitrogen dioxide and sulfur dioxide, which can lead to acid rain. However, their contribution to air pollution is not as significant as that of motor vehicles in recent times.
- **Motor Vehicles**: Motor vehicles, including cars and trucks, are a major source of air pollution. They emit a significant amount of carbon dioxide (CO2), which is a greenhouse gas and a leading contributor to global warming.
- **Domestic Appliances**: While domestic appliances can cause indoor air pollution (e.g., carbon monoxide from gas stoves), their overall impact on outdoor air pollution is less than that of motor vehicles.
- **Animals**: Animals themselves are not pollutants. They are affected by pollution and climate change, but they do not contribute to air pollution.

3. **Determine the Correct Answer**: Based on the analysis, motor vehicles are identified as the greatest air pollutant these days due to their increasing numbers and the high emissions of CO2 they produce.

4. **Conclusion**: The correct answer to the question is **motor vehicles**.

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