It always happens in the winter: as soon as the heating period begins, a black layer forms out of nowhere and settles securely on the walls. KEIM mineral paints have been proved to NOT contribute to this phenomenon.
Many widely available interior wall paints contain so-called volatile organic compounds (plasticisers) as are usually found in many plastics. They are mostly odour-free plasticisers which don't need to be declared and, for this reason, they are often "invisible" for the customer. Plasticisers emit continuously from the coats of paint over the course of many months.
In addition to the health risks involved, plasticisers can also cause this phenomen as mentioned in the introduction, which involves walls and ceilings being covered in a black layer made of plasticisers and dust particles that are released when the rooms are heated. Why? Dust particles in the room stick firmly to the emitted plasticiser particles and then settle on the walls, mostly in areas where the air circulates.
KEIM paints ensure brilliant white walls!