Explain the differences between pure air and polluted air.

Explanation

### Step-by-Step Text Solution

1. **Definition of Pure Air**:
- Pure air is defined as clean air that is free from pollution and harmful substances. It contains a balanced composition of gases essential for life.

2. **Composition of Pure Air**:
- Pure air typically consists of approximately 78% nitrogen, 21% oxygen, and a small percentage of other gases like argon, carbon dioxide, and trace gases. Importantly, it does not contain harmful pollutants.

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