A wood shop could be a very bad place for you, in regards to your lungs. Without a good dust collection system, you are breathing in very fine airborne dust. And by system, it isn't just collecting the sawdust from your machines you need to be concerned with.
Ambient dust is probably more of a threat to your health than the saw dust at the back of you machines. If you've ever seen a wood shop with sunlight pouring in through a window, the amount of dust floating in the air can be quite alarming.
I used to notice when visiting professional mill work shops twenty some years ago, had no dust collection systems other than the machine hook ups, but the air was filled with fine dust particles, which the workers were breathing, as they wore no masks. No one seemed to notice or care that they were breathing this dust in for eight hours a day. I can only imagine the condition of their lungs today.
The importance of ambient air filtration can't be over stated. If you're unable to afford a filtration system, wear a mask! Lung capacity decreases and is accumulative, meaning the damage happens little by little, and adds up.
The air filtration units that hang from the ceiling are very effective, are relatively inexpensive. I have one at each end of my shop. Splitting the space into thirds. They are also beneficial in reducing the dust entering your heating and cooling system.
In addition to the ambient air dust collection is the system used at each machine. These units generally have a grounded ducting running from the dust collector itself, to each machine. In a home shop, either P.V.C. plastic drain lines, or metal ducts are used to pipe in each machine.
Just before each machine the duct will have a blast gate. These are either manually or electronically controlled. Manual gates are simply opened and closed at the machine you wish to use. The electronic gates are activated by turning the machine on or off.
A grounding wire is important for a P.V.C. duct system in particular, due to static electric created by the air rushing through the ducts. Wood dust is combustible so having a spark inside the duct can lead to a fire, quite easily.
Metal ducting is easier to ground as it is metal, so fastening the sections together is grounding the runs. The end of the duct should be grounded. With a metal cyclone system, the unit is grounded, so the ducting is as well, once they're screwed together. If the duct is connected to a shop vacuum, a ground wire should be fastened to the metal duct.
Shopsmith makes a dust collector that is very good for the home wood shop. It will clean the air in the shop, as well as handle saw dust collection for your machines. It can be hooked up to duct work, or connected to individual machines as needed.
An advantage they have over a shop vacuum is they are quieter than most vacuums, and have greater air flow volume. This is due to the squirrel cage style fan, similar to ones found in forced air heating and cooling systems. These units are very convenient for both home and job site use.