They will not seetle down because light is only a medium to see them it has no relation with the settlement of particles. Hope this helps
Yes, they still moves but we cant see them. And we can again see them when we get light. As they are visible only when light is there we cant see them.
The sunlight is just a medium to see those particles.The particles may settle down or move in the air.So it does not depends on the sunlight.