We moved some time ago and in the new washroom there is a lot of dust on the surfaces (I clean it nearly every day but next day there is a new layer). Only source I could imagine is the ventilation system. My guess is there is a missing part like a fabric layer or something on top of the shown part on the picture.
Is this assumption right and how could I add it?
Addition: On one outer side of the washroom is a fireplace. Once we start the ventilation (button for it like for light) when the fireplace is burning, the smoke comes into the washroom.