Fogging black dust - Who can share their experience with us!

We have the problem of fogging. Who has already had experience with it? We have renovated our condominium twice and the phenomenon keeps recurring. In March of this year, we had a building biologist here who also took samples. The whole thing is very unclear. Who can tell us something about it?

Fogging is not yet properly researched. Generally, it occurs frequently with rising air, as far as I know. For example, above radiators. In our old apartment, we had a similar symptom above the spot where my living room PC and my radio receiver were located. Next to it was also a radiator. At my parents' place, a similar effect was observed above a frequently used radiator. The hi-fi system was also not far away there. What is underneath or what technology is nearby on your side?

What time periods are we talking about here? So how long from the last paint job until visibly disturbing spots appear?

Fogging is probably related on the one hand to cool walls and on the other hand to a lot of plastic in the living spaces. Therefore the question: what kind of floor coverings do you have? Do you have new furniture? What material are your curtains made of, etc.

So in terms of technology, we have a Smart TV. The flooring we have is vinyl laminate with cork as insulation. The renovation before moving in was in October 2015, the next renovation was in October 2018... every time a few weeks after the renovation the phenomenon occurred... We have no new furniture...

.. well, you have already given yourself the answer...