Just simple physics

There is nothing mysterious about the ability of the Green Belt to clear the air. It´s just simple physics. Look at the animated gif to the left!

The brownish shape in the middle is a dust particle and the blue shapes are water vapour.

When dust particles blow in at a normally low altitude they become condensation nucleii:

Air borne vapour condensates as water on the surface of the dust particle. The particle attracts more and more vapour. The particle becomes heavy and sinks. Vapourized water from the trees in the Green Belt bind dust.

It´s that easy: just simple physics.