How should I set my aperture to be able to capture dust particles

You should clean your room.

>>2955856
Doesn't matter as long as your focus is on the section in which light illuminates the dust particles. The smaller the apperture, the bigger your focused area (DOF). Although if you're making those shots indoors you'll need big appertures such as 2.8 or 4.

The key to capture those particles is light, direct beams striking them.

>>2958146
Thanks man

>>2958146
this, and a fast shutter speed too

>>2955856
Those are dead skin cells in all likelihood

>>2958428
Thanks for defining what dust is for all of us