Read as much of this info as you can absorb.
It is detailed and tedious, BUT you will know way more about collection methods, systems, dust and particle size and how to best keep a dist free shop area.
I'll tell you what I do.
I use 3 different dust collection systems:
(1) Jet 1100 1 1/2 HP dust collector with 4" flex hose kept to a minimum
to collect dust and chips at the large machines.
(2) Jet 3 speed AFS 1000 overhead dust filtration unit to collect floating airborne dust in the shop air.
(3) Several Rigid 16 gal shop vacs attached to the small dust ports on router tables, miter saws, radial arm saws and all ROS hand held sanders.
You need all 3 types to really do the best job of dust collection. Here's why. Fine dust particles will float in the air and settle on horizontal surfaces IF they are not immediately collected right at their source. A high velocity shop vac is the best device to collect "at source" generated dust. It needs to be within 2" of the source to do the best job. Grab a handful of dust and slowly let it fall in front of your shop vac hose at various distances and you'll see what I mean.
An older table saw is a very difficult unit to collect dust because of the open space inside the cabinet and lack of a shroud that encloses the blade. Once the dust is spun off the blade it may shoot out the top of the table, but most will end up inside the cabinet, falling down from it's own weight before it gets sucked into and 4" dust collection hose at the base of the cabinet. That's just how it works.
Once the fine dust get airborne, you need to move a lot of air through an overhead filtration device to "scrub" it out. The AFS 1000 has two internal filters for this reason.
Different approaches are used depending on the shop location and whether you can exhaust dust to the outside OR you have to filter it well enough to recycle the air back inside the shop area. Those final filters are vital in determining the particle size that gets pushed back into the air you are breathing. Bags are the least effective, and cannisters are the best because they have so much more surface area and a finer filter media.
You need to understand that a dust collector is really a high volume air pump, not a suction device. It creates suction by displacing the air it takes in and pumps it through a filter, under pressure. The better and larger the filter, the cleaner the air that passes through it and the cleaner the air you end up breathing.