[Mando]

Wazza is right, concrete expels dust for quite a while until it develops a seal either naturally through use or sealing with an appropriate product.
If you intend sealing the floor, the best thing you could do is to follow Peter Craig's directions. The only thing I would add is to make certain the floor is 100% dry before applying the sealer. If you can leave the floor for 24 hours or heat the room for a while then return the room to normal temp.

Regards.