Pure air | Polluted air |
1. Pure air contains around 78% nitrogen, 21% oxygen and 0.03% carbon dioxide. | 1. Polluted air has no such definite composition of these gases. |
2. Other gases such as argon, methane, ozone, and water vapours are also present in small quantities. | 2. Polluted air has harmful gases like nitrogen dioxide, sulphur dioxide, carbon monoxide, particulate matter etc. |
3. It is fresh and healthy for lungs. | 3. It can cause respiratory diseases. |