Which one of these is the biggest factor responsible for air pollution across the world today?

Options

A. Industrial emission
B. Vehicular emission
C. Volcanic eruptions
D. Oil spills

Explanation

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the biggest factor responsible for air pollution globally today. We need to evaluate the provided options: industrial emissions, vehicular emissions, volcanic eruptions, and oil spills.

2. **Analyzing Each Option**:
- **Industrial Emissions**: These are significant contributors to air pollution, especially in industrialized regions. However, they are not the largest contributor when compared to vehicular emissions.
- **Vehicular Emissions**: This refers to the pollutants released from vehicles, including cars, trucks, and buses. With the increase in population and urbanization, the number of vehicles on the road has surged, leading to a significant rise in air pollution.
- **Volcanic Eruptions**: While volcanic eruptions can cause temporary spikes in air pollution, they are not a constant source like vehicular emissions.
- **Oil Spills**: These primarily affect water bodies and do not contribute significantly to air pollution.

3. **Identifying the Largest Factor**: After evaluating all options, it becomes clear that vehicular emissions are the largest contributor to air pollution today. The rapid increase in population leads to more vehicles, which in turn increases emissions.

4. **Conclusion**: Therefore, the biggest factor responsible for air pollution across the world today is **vehicular emissions**.