Creating quite some dust in my workshop I came to the conclusion that a big air filter would be good for my lungs.
I bought a big radial fan from EBM Papst from Ebay for roughly 70 Euro. It consumes ~30W and created a quite impressive air flow while being really quite.
I combined them in a single box together with two filter cassettes. One being relatively rough used as a first filter. And a second one with a really fine mesh to filter smallest particles.
The box is mounted to the ceiling with two ropes to prevent vibrations to spread into the roof construction.