Dust and air quality

Hi all,
I’m in the process of making my cabinet workshop a more healthy place to work. I’ll be buying a new power tool extractor (Nilfisk Attix 33-2m or Dewalt DMV902m) and fitting an air cleaner.
I would like to measure the dust in the air to see the improvement and be sure it’s working as you can’t see fine sanding dust.
Can anyone point me in the direction of a basic dust monitor (sub €50) or explain what the readings tell me?
Thanks all

Didn’t even know those existed.

I’ve always lived by the description of, “If you can smell it, there’s too much.”