Why does air in a room show the Tyndall effect?

Tyndall effect is the scattering of light by the particles of a solution.

Colloidal solutions are those in which the size of particles is not visible to naked eyes but they can scatter the beam of light.

Now, air in the room is not just a homogenous mixture of gases but it also has dust particles and smoke that scatter the light falling on them. Thus, due to the presence of these impurities, air in the room shows the Tyndall effect.