Which among the given is not a natural source of air pollution?

Options

A. Automobile exhausts
B. Vegetation decay
C. Forest fire
D. Volcanic eruptions

Answer

To determine which among the given options is not a natural source of air pollution, we can analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Air Pollution**:
- Air pollution refers to the introduction of harmful substances into the atmosphere, which can be caused by both natural and human-made activities.

2. **Analyzing the Options**:
- **Option 1: Automobile Exhaust**
- This is produced by vehicles and is a result of human activities. Therefore, it is considered man-made pollution.

- **Option 2: Vegetation Decay**
- This process occurs naturally as plants decompose, releasing gases like carbon dioxide and methane into the atmosphere. Hence, it is a natural source of air pollution.

- **Option 3: Forest Fire**
- Forest fires can occur naturally due to lightning strikes or other natural causes. They release smoke and other pollutants into the air, making them a natural source of air pollution.

- **Option 4: Volcanic Eruption**
- Volcanic eruptions are natural events that release ash, gases, and other particulates into the atmosphere, contributing to air pollution. Thus, this is also a natural source.

3. **Identifying the Correct Answer**:
- After analyzing all the options, it is clear that **Option 1: Automobile Exhaust** is the only option that is not a natural source of air pollution.

### Final Answer:
The correct answer is **Option 1: Automobile Exhaust**.

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