Which one of these natural phenomena does NOT cause air pollution?

Options

A. Dust storm
B. Forest fire
C. Volcanic eruption
D. Agricultural run-off

Explanation

To determine which natural phenomenon does NOT cause air pollution, we need to analyze each option provided:

1. **Dust Storms**: Dust storms are caused by strong winds that lift dust and sand particles from the ground into the air. These particles are classified as particulate matter, which can cause respiratory issues when inhaled. Therefore, dust storms do contribute to air pollution.

2. **Forest Fires**: Forest fires occur when vegetation burns, releasing various pollutants into the air, including carbon dioxide, nitrogen oxides, and particulate matter. This means that forest fires also contribute to air pollution.

3. **Volcanic Eruptions**: Volcanic eruptions release a significant amount of gases, including sulfur dioxide, which can lead to respiratory problems and contribute to acid rain. Thus, volcanic eruptions are also a source of air pollution.

4. **Agricultural Runoff**: Agricultural runoff primarily refers to water that carries fertilizers, pesticides, and other chemicals from agricultural fields into nearby water bodies. While it can lead to water pollution, it does not directly release pollutants into the air. Therefore, agricultural runoff does NOT cause air pollution.

**Conclusion**: The natural phenomenon that does NOT cause air pollution is **Agricultural Runoff**.