I recently posted the outdoor air pollution levels as we have had a lot of smoke from the Canadian Wildfires and showed unhealthy levels.
I measured it with one like this that I saw on Amazon with the description and was about $49
"HOTKREM Air Quality Monitor pm2.5 pm10 pm1.0 Detector Indoor air Quality Test kit for Cars,Home,Office,Hotel etc (PM2.5,AQI)"
Similar are available on Ebay for lower prices.
I tried placing right next to my Hegner scroll saw and cut 1/4' Baltic Birch. The higher number was with my vacuum off and lower with it on. It shows the value of using dust collection on your saw especially if you are sawing for a long time. The smaller dust particles that are 1 um and smaller are not visible but still dangerous to your health especially if you are older.
Next, I placed it beside my small belt sander and the numbers were very high as expected.
Lastly, I placed it on my table saw and cut off the edge of 1/2 plywood several times with the following results.
Kind of as expected, the belt sander was the worst for putting unhealthy dust in the air and points out that I need to get some dust collection on it. As a comparison, here is the air quality I experienced outside this week. It is worse for the PM2.5 than most things in my shop.