The layer of paint quickly becomes covered with dust, that may resemble mould.
Causes:
Poor quality paint, particularly in the case of fully matted or matted degree of gloss;
Accumulation of air pollution, car emissions and flying dust on the house façade and horizontal surfaces.
Solution:
Remove the dirt from the painted surface with water or cleaning liquid. If you are not sure whether the dustiness is caused by dirt or by mould, make a quick check. Then carefully rinse the surface with water using a sponge or pressure cleaner. Dust accumulation is a natural process, but high-quality paints are more resistant to dust. Paints with a higher degree of gloss accumulate less dust.