Hello. You need two pieces of equipment to be dust free if you're cutting wood in your garage. I'm looking at this myself.
The first thing I would get is a dust collection unit. Delta makes a portable unit that is compact and draws 650 cfm.
My friend just bought this one for $200 CDN on sale. I would buy this one for myself.
http://www.deltawoodworking.com/cata...odel_no=50-775
If there is still too much sawdust in the air for your liking, then you need an air filtration system that will clean the air so many times in an hour. There are different sized unit dependiing on the volume of space that you have. These are more money.. like over double than the dust collector.
http://www.deltawoodworking.com/cata....asp?cat_id=20
Hope this helps,
Harry.