What is aerosol?

Explanation

### Step-by-Step Text Solution:

1. **Definition of Aerosol**: An aerosol is defined as a suspension of fine solid particles and liquid droplets in the air.

2. **Size of Aerosols**: The diameter of aerosol particles is typically less than 1 micrometer. This small size allows them to remain suspended in the atmosphere for extended periods.

3. **Sources of Aerosols**: Aerosols can originate from both natural and anthropogenic (human-made) sources:
- **Natural Sources**: These include phenomena such as fog, mist, and forest exudates (substances released by trees).
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