Here's why:

* Dust: Air contains tiny particles of dust, dirt, pollen, and other materials.

* Water Vapor: Air can hold varying amounts of water vapor, which is water in its gaseous state.

* 75% of all gases: The primary component of air is nitrogen, which makes up about 78% of the atmosphere. Oxygen is the second most abundant gas, making up about 21%. The remaining 1% includes other gases like carbon dioxide, argon, and trace amounts of other elements.

Let me know if you have any other questions!